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Flowers, serving as the reproductive structures of angiosperms, perform an integral role in plant biology and are fundamental to understanding plant evolution and taxonomy. The growth and organogenesis of flowers are driven by numerous factors, such as external environmental conditions and internal physiological processes, resulting in diverse traits across species or even within the same species. Among these factors, genes play a central role, governing the entire developmental process. The regulation of floral genesis by these genes has become a significant focus of research. In the AE model of floral development, the five structural whorls (calyx, corolla, stamens, pistils, and ovules) are controlled by five groups of genes: A, B, C, D, and E. These genes interact to give rise to a complex control system that governs the floral organsgenesis. The activation or suppression of specific gene categories results in structural modifications to floral organs, with variations observed across different species. The present article examines the regulatory roles of key genes, including genes within the MADS-box and AP2/ERF gene clusters, such as AP1, AP2, AP3, AG, STK, SHP, SEP, PI, and AGL6, as well as other genes, like NAP, SPL, TGA, PAN, and WOX, in shaping floral organ genesis. In addition, it analyzes the molecular-level effects of these genes on floral organ formation. The findings offer a deeper understanding of the genetic governance of floral organ genesis across plant species. [ABSTRACT FROM AUTHOR]

Most of the studied MADS box members are linked to flowering and fruit traits. However, higher volumes of studies on type II of the two types so far suggest that the florigenic effect of the gene members could just be the tip of the iceberg. In the current study, we used a systematic approach to obtain a general overview of the MADS box members' cross-trait and multifactor associations, and their pleiotropic potentials, based on a manually curated local reference database. While doing so, we screened for the co-occurrence of terms of interest within the title or abstract of each reference, with a threshold of three hits. The analysis results showed that our approach can retrieve multi-faceted information on the subject of study (MADS box gene members in the current case), which could otherwise have been skewed depending on the authors' expertise and/or volume of the literature reference base. Overall, our study discusses the roles of MADS box members in association with plant organs and trait-linked factors among plant species. Our assessment showed that plants with most of the MADS box member studies included tomato, apple, and rice after Arabidopsis. Furthermore, based on the degree of their multi-trait associations, FLC, SVP, and SOC1 are suggested to have relatively higher pleiotropic potential among others in plant growth, development, and flowering processes. The approach devised in this study is expected to be applicable for a basic understanding of any study subject of interest, regardless of the depth of prior knowledge. [ABSTRACT FROM AUTHOR]

MADS-box is a key transcription factor regulating the transition to flowering and flower development. Lagerstroemia indica 'Xiang Yun' is a new cultivar of crape myrtle characterized by its non-fruiting nature. To study the molecular mechanism underlying the non-fruiting characteristics of 'Xiang Yun', 82 MADS-box genes were identified from the genome of L. indica. The physicochemical properties of these genes were examined using bioinformatics methods, and their expression as well as endogenous hormone levels at various stages of flower development were analyzed. The results showed that LiMADS genes were primarily classified into two types: type I and type II, with the majority being type II that contained an abundance of cis-acting elements in their promoters. By screening nine core proteins by predicted protein interactions and performing qRT-PCR analysis as well as in combination with transcriptome data, we found that the expression levels of most MADS genes involved in flower development were significantly lower in 'Xiang Yun' than in the wild type 'Hong Ye'. Hormonal analysis indicated that 'Xiang Yun' had higher levels of iP, IPR, TZR, and zeatin during its early stages of flower development than 'Hong Ye', whereas the MeJA content was substantially lower at the late stage of flower development of 'Hong Ye'. Finally, correlation analysis showed that JA, IAA, SA, and TZR were positively correlated with the expression levels of most type II genes. Based on these analyses, a working model for the non-fruiting 'Xiang Yun' was proposed. During the course of flower development, plant hormone response pathways may affect the expression of MADS genes, resulting in their low expression in flower development, which led to the abnormal development of the stamen and embryo sac and ultimately affected the fruiting process of 'Xiang Yun'. [ABSTRACT FROM AUTHOR]

MADS-box is a key transcription factor regulating the transition to flowering and flower development. Lagerstroemia indica ‘Xiang Yun’ is a new cultivar of crape myrtle characterized by its non-fruiting nature. To study the molecular mechanism underlying the non-fruiting characteristics of ‘Xiang Yun’, 82 MADS-box genes were identified from the genome of L. indica. The physicochemical properties of these genes were examined using bioinformatics methods, and their expression as well as endogenous hormone levels at various stages of flower development were analyzed. The results showed that LiMADS genes were primarily classified into two types: type I and type II, with the majority being type II that contained an abundance of cis-acting elements in their promoters. By screening nine core proteins by predicted protein interactions and performing qRT-PCR analysis as well as in combination with transcriptome data, we found that the expression levels of most MADS genes involved in flower development were significantly lower in ‘Xiang Yun’ than in the wild type ‘Hong Ye’. Hormonal analysis indicated that ‘Xiang Yun’ had higher levels of iP, IPR, TZR, and zeatin during its early stages of flower development than ‘Hong Ye’, whereas the MeJA content was substantially lower at the late stage of flower development of ‘Hong Ye’. Finally, correlation analysis showed that JA, IAA, SA, and TZR were positively correlated with the expression levels of most type II genes. Based on these analyses, a working model for the non-fruiting ‘Xiang Yun’ was proposed. During the course of flower development, plant hormone response pathways may affect the expression of MADS genes, resulting in their low expression in flower development, which led to the abnormal development of the stamen and embryo sac and ultimately affected the fruiting process of ‘Xiang Yun’.

Abstract Background Non-synchronized pods shattering in the Brassicaceae family bring upon huge yield losses around the world. The shattering process was validated to be controlled by eight genes in Arabidopsis, including SHP1, SHP2, FUL, IND, ALC, NAC, RPL, and PG. We performed genome-wide identification, characterization, and expression analysis of shattering genes in B.napus and B. juncea to gain understanding into this gene family and to explain their expression patterns in fresh and mature siliques. Results A comprehensive genome investigation of B.napus and B.juncea revealed 32 shattering genes, which were identified and categorized using protein motif structure, exon-intron organization, and phylogeny. The phylogenetic study revealed that these shattering genes contain little duplications, determined with a distinct chromosome number. Motifs of 32 shattering proteins were observed where motifs1 and 2 were found to be more conserved. A single motif was observed for other genes like Br-nS7, Br-nS9, Br-nS10, Br-jS21, Br-jS23, Br-jS24, Br-jS25, and Br-jS26. Synteny analysis was performed that validated a conserved pattern of blocks among these cultivars. RT-PCR based expressions profiles showed higher expression of shattering genes in B. juncea as compared to B.napus. SHP1, SHP2, and FUL gene were expressed more in mature silique. ALC gene was upregulated in fresh silique of B. napus but downregulation of ALC were observed in fresh silique of B. juncea. Conclusion This study authenticates the presence of shattering genes in the local cultivars of Brassica. It has been validated that the expression of shattering genes were more in B. juncea as compared to B.napus. The outcomes of this study contribute to the screening of more candidate genes for further investigation.

The 1991 review paper by Coen andMeyerowitz on the control of floral organ development set out the evidence available at that time, which led to the now famous ABCmodel of floral organ identity control. The authors summarised the genetic and molecular analyses that had been carried out in a relatively short time by several laboratories, mainly in Arabidopsis thaliana and Antirrhinummajus.Theworkwas a successful example of howsystematic genetic andmolecular analysis can decipher themechanismthat controls a developmental process in plants.The ABC model is a combinatorialmodel inwhicheachfloral whorl acquires its identity throughaunique combination of floral homeotic gene activities.The review also highlights the similarities in the regulation of floral organ identity between evolutionarily distant plant species, emphasising the general relevance of the model and paving the way for comprehensive studies of the evolution of floral diversity. [ABSTRACT FROM AUTHOR]

Background: Non-synchronized pods shattering in the Brassicaceae family bring upon huge yield losses around the world. The shattering process was validated to be controlled by eight genes in Arabidopsis, including SHP1, SHP2, FUL, IND, ALC, NAC, RPL, and PG. We performed genome-wide identification, characterization, and expression analysis of shattering genes in B.napus and B. juncea to gain understanding into this gene family and to explain their expression patterns in fresh and mature siliques. Results: A comprehensive genome investigation of B.napus and B.juncea revealed 32 shattering genes, which were identified and categorized using protein motif structure, exon-intron organization, and phylogeny. The phylogenetic study revealed that these shattering genes contain little duplications, determined with a distinct chromosome number. Motifs of 32 shattering proteins were observed where motifs1 and 2 were found to be more conserved. A single motif was observed for other genes like Br-nS7, Br-nS9, Br-nS10, Br-jS21, Br-jS23, Br-jS24, Br-jS25, and Br-jS26. Synteny analysis was performed that validated a conserved pattern of blocks among these cultivars. RT-PCR based expressions profiles showed higher expression of shattering genes in B. juncea as compared to B.napus. SHP1, SHP2, and FUL gene were expressed more in mature silique. ALC gene was upregulated in fresh silique of B. napus but downregulation of ALC were observed in fresh silique of B. juncea. Conclusion: This study authenticates the presence of shattering genes in the local cultivars of Brassica. It has been validated that the expression of shattering genes were more in B. juncea as compared to B.napus. The outcomes of this study contribute to the screening of more candidate genes for further investigation. [ABSTRACT FROM AUTHOR]

Background: APETALA3 (AP3) has significant roles in petal and stamen development in accordance with the classical ABC model. Results: The AP3 homolog, CDM19, from Chrysanthemum morifolium cv. Jinba was cloned and sequenced. Sequence and phylogenetic analyses revealed that CDM19 is of DEF/AP3 lineage possessing the characteristic MIKC-type II structure. Expression analysis showed that CDM19 was transcribed in petals and stamens of ray and disc florets with weak expression in the carpels. Ectopic expression of CDM19 in Arabidopsis wild-type background altered carpel development resulting in multi-carpel siliques. CDM19 could only partially rescue the Arabidopsis ap3‐–3 mutant. Conclusions: Our results suggest that CDM19 may partially be involved in petal and stamen development in addition to having novel function in carpel development.How to cite: Githeng’u SK, Ding L, Zhao K, et al. Ectopic expression of Chrysanthemum CDM19 in Arabidopsis reveals a novel function in carpel development. Electron J Biotechnol 2020;45. https://doi.org/10.1016/j.ejbt.2020.03.001.

MADS box genes are class of transcription factors involved in various physiological and developmental processes in plants. To understand their role in floral transition-related pathways, a genome-wide identification was done in Cajanus cajan, identifying 102 members which were classified into two different groups based on their gene structure. The status of all these genes was further analyzed in three wild species i.e. C. scarabaeoides, C. platycarpus and C. cajanifolius which revealed absence of 31–34 MADS box genes in them hinting towards their role in domestication and evolution. We could locate only a single copy of both FLOWERING LOCUS C (FLC) and SHORT VEGETATIVE PHASE (SVP) genes, while three paralogs of SUPPRESSOR OF ACTIVATION OF CONSTANS 1 (SOC1) were found in C. cajan genome. One of those SOC1 paralogs i.e. CcMADS1.5 was found to be missing in all three wild relatives, also forming separate clade in phylogeny. This SOC1 gene was also lacking the characteristic MADS box domain in it. Expression profiling of major MADS box genes involved in flowering was done in different tissues viz shoot apical meristem, vegetative leaf, reproductive meristem, and reproductive bud. Gene-based time tree of FLC and SOC1 gene dictates their divergence from Arabidopsis before 71 and 23 million year ago (mya), respectively. This study provides valuable insights into the functional characteristics, expression pattern, and evolution of MADS box proteins in grain legumes with emphasis on C. cajan, which may help in further characterizing these genes. [ABSTRACT FROM AUTHOR]

Ｉｎ ｏｒｄｅｒ ｔｏ ｕｎｃｏｖｅｒ ｔｈｅ ｍｏｌｅｃｕｌａｒ ｍｅｃｈａｎｉｓｍ ｏｆ ｆｌｏｗｅｒ ｏｒｇａｎ ｄｅｖｅｌｏｐｍｅｎｔ ｒｅｇｕｌａｔｉｏｎ ｏｆ Ｃｙｍｂｉｄｉｕｍ ｇｏｅｒｉｎｇｉｉ ａｎｄ ｖａｒｉｅｔｉｅｓ ｗｉｔｈ ａｂｎｏｒｍａｌ ｆｌｏｗｅｒꎬ ａ ｃＤＮＡ ｗａｓ ｃｌｏｎｅｄ ｆｒｏｍ ｔｈｅ ｆｌｏｗｅｒ ｂｕｄｓ ｏｆ ｔｈｅ ｃｏｍｍｏｎ Ｃ. ｇｏｅｒｉｎｇｉｉ ａｎｄ Ｃ. ｇｏｅｒｉｎｇｉｉ ‘Ｔｉａｎ Ｐｅｎｇ Ｍｕ Ｄａｎ’ ｂｙ ｈｏｍｏｌｏｇｏｕｓ ｃｌｏｎｉｎｇ ｍｅｔｈｏｄ. Ｔｈｅ ８４９ ｂｐ Ｄ-ｃｌａｓｓ ＭＡＤＳ-ｂｏｘ ｇｅｎｅ ＣｙｇｏＳＴＫ (Ｇｅｎｂａｎｋ ａｃｃｅｓｓｉｏｎ ｎｕｍｂｅｒ ｉｓ ＭＨ９１７９１２.１)ꎬ ｗｈｉｃｈ ｗａｓ ｈｉｇｈ ｉｄｅｎｔｉｔｙ ｉｎ Ｃ. ｇｏｅｒｉｎｇｉｉ ａｎｄ Ｃ. ｇｏｅｒｉｎｇｉｉ ‘Ｔｉａｎ Ｐｅｎｇ Ｍｕ Ｄａｎ’ꎬ ｃｏｎｔａｉｎｅｄ ａ ７０５ ｂｐ ｃｏｍｐｌｅｔｅ ＯＲＦꎬ ｅｎｃｏｄｉｎｇ ２３４ ａｍｉｎｏ ａｃｉｄ ｒｅｓｉｄｕｅｓꎻ Ｐｒｏｔｅｉｎ ａｌｉｇｎｍｅｎｔ ａｎｄ ａ ｐｈｙｌｏｇｅｎｅｔｉｃ ｔｒｅｅ ｇｒｏｕｐｅｄ ＣｙｇｏＳＴＫ ｉｎｔｏ ｔｈｅ ＳＴＫ ｌｉｎｅａｇｅ. Ｓｔｒｕｃｔｕｒａｌ ａｎａｌｙｓｉｓ ｓｈｏｗｅｄ ｔｈａｔ ＣｙｇｏＳＴＫ ｔｒａｎｓｃｒｉｐｔｉｏｎ ｆａｃｔｏｒ ｃｏｎｔａｉｎｅｄ ａ ｈｉｇｈｌｙ ｃｏｎｓｅｒｖｅｄ ＭＡＤＳ ｄｏｍａｉｎ (１－５７) ａｎｄ ａ ｓｅｃｏｎｄａｒｙ ｃｏｎｓｅｒｖｅｄ Ｋ ｄｏｍａｉｎ (９１－１７２)ꎻ Ｉｎ ａｄｄｉｔｉｏｎꎬ ｔｈｅ Ｃ-ｔｅｒｍｉｎａｌ ｔｒａｎｓｃｒｉｐｔｉｏｎａｌ ａｃｔｉｖａｔｉｏｎ ｒｅｇｉｏｎ ｏｆ ＣｙｇｏＳＴＫ ｃｏｎｔａｉｎｅｄ ｔｗｏ ｈｉｇｈｌｙ ｃｏｎｓｅｒｖｅｄ ｍｏｔｉｆｓ: ＡＧＩ ｍｏｔｉｆ ａｎｄ ＡＧⅡｍｏｔｉｆ. Ｆｕｒｔｈｅｒｍｏｒｅꎬ ｔｈｅ ｒｅｌａｔｉｖｅ ｅｘｐｒｅｓｓｉｏｎ ｏｆ ＣｙｇｏＳＴＫ ｇｅｎｅ ｉｎ ｄｉｆｆｅｒｅｎｔ ｆｌｏｒａｌ ｏｒｇａｎｓ ｏｆ Ｃ. ｇｏｅｒｉｎｇｉｉ ａｎｄ Ｃ. ｇｏｅｒｉｎｇｉｉ ‘Ｔｉａｎ Ｐｅｎｇ Ｍｕ Ｄａｎ’ ｗａｓ ｄｅｔｅｃｔｅｄ ｂｙ ｑＰＣＲ. Ｏｕｒ ｄａｔａ ｓｕｇｇｅｓｔｅｄ ｔｈａｔ ＣｙｇｏＳＴＫ ｅｘｐｒｅｓｓｉｏｎ ｗａｓ ｔｈｅ ｈｉｇｈｅｓｔ ｉｎ ｔｈｅ ｏｖａｒｙ ｏｆ ｃｏｍｍｏｎ Ｃ. ｇｏｅｒｉｎｇｉｉ ａｎｄ Ｃ. ｇｏｅｒｉｎｇｉｉ ‘Ｔｉａｎ Ｐｅｎｇ Ｍｕ Ｄａｎ’ꎬ ｗｈｉｃｈ ｗａｓ ｓｉｇｎｉｆｉｃａｎｔｌｙ ｈｉｇｈｅｒ ｔｈａｎ ｔｈａｔ ｏｆ ｔｈｅ ｏｔｈｅｒ ｆｌｏｒａｌ ｏｒｇａｎｓ (ＬＳＤꎬＰ<０.０５). Ｏｕｒ ｒｅｓｕｌｔｓ ｉｎｄｉｃａｔｅ ｔｈａｔ ｔｈｅ ｆｕｎｃｔｉｏｎ ｏｆ ＣｙｇｏＳＴＫ ｇｅｎｅ ｉｓ ｈｉｇｈｌｙ ｃｏｎｓｅｒｖｅｄ ａｎｄ ＣｙｇｏＳＴＫ ｉｓ ｍａｉｎｌｙ ｉｎｖｏｌｖｅｄ ｉｎ ｒｅｇｕｌａｔｉｎｇ ｔｈｅ ｏｖａｒｙ ｄｅｖｅｌｏｐｍｅｎｔ ｏｆ Ｃ. ｇｏｅｒｉｎｇｉｉ. [ABSTRACT FROM AUTHOR]

Rosaceae (the rose family) is an economically important family that includes species prized for high-value fruits and ornamentals. The family also exhibits diverse fruit types, including drupe (peach), pome (apple), drupetum (raspberry), and achenetum (strawberry). Phylogenetic analysis and ancestral fruit-type reconstruction suggest independent evolutionary paths of multiple fleshy fruit types from dry fruits. A recent whole genome duplication in the Maleae/Pyreae tribe (with apple, pear, hawthorn, and close relatives; referred to as Maleae here) may have contributed to the evolution of pome fruit. MADS-box genes, known to regulate floral organ identity, are emerging as important regulators of fruit development. The differential competence of floral organs to respond to fertilization signals may explain the different abilities of floral organs to form fleshy fruit. Future comparative genomics and functional studies in closely related Rosaceae species with distinct fruit types will test hypotheses and provide insights into mechanisms of fleshy fruit diversity. These efforts will be facilitated by the wealth of genome data and resources in Rosaceae. [ABSTRACT FROM AUTHOR]

MADS box transcription factors have been studied extensively in flowering plants but remain less studied in non-seed plants. MADS box is one such example of a gene which is prevalent across many classes of plants ranging from chlorophyta to embryophyta as well as fungi and animals. MADS box transcription factors are of two types, Type I and Type II. Type II transcription factors (TF) that consist of a MADS domain, I region, K domain, and C terminal domain are discussed in this review. The Type II/ MIKC class is widespread across charophytes and all major lineages of land plants but unknown in green and red algae. These transcription factors have been implicated in floral development in seed plants and thus the question arises, “What is their role in non-seed plants?” From the studies reviewed here it can be gathered that unlike seed plants, MIKCC genes in non-seed plants have roles in both gametophytic and sporophytic generations and contribute to the development of both vegetative and reproductive structures. On the other hand as previously observed in seed plants, MIKC* genes of non-seed plants have a conserved role during gametophyte development. With respect to evolution of MIKC genes in non-seed plants, the number of common ancestors is probably very few at each branch. The expansion of this gene family in seed plants and increased plant complexity seem to be correlated. As gradually the genomes of non-seed plants are becoming available it is worthwhile to gather the existing information about MADS box genes in non-seed plants. This review highlights various MIKC MADS box genes discovered so far in non-seed plants, their possible roles and an insight into their evolution.

Background: Harvest time is a relevant economic trait in citrus, and selection of cultivars with different fruit maturity periods has a remarkable impact in the market share. Generation of early- and late-maturing cultivars is an important target for citrus breeders, therefore, generation of knowledge regarding the genetic mechanisms controlling the ripening process and causing the early and late phenotypes is crucial. In this work we analyze the evolution of the transcriptome during fruit ripening in 3 sport mutations derived from the Fina clementine (Citrus clementina) mandarin: Clemenules (CLE), Arrufatina (ARR) and Hernandina (HER) that differ in their harvesting periods. CLE is considered a mid-season cultivar while ARR and HER are early- and late-ripening mutants, respectively. Results: We used RNA-Seq technology to carry out a time course analysis of the transcriptome of the 3 mutations along the ripening period. The results indicated that in these mutants, earliness and lateness during fruit ripening correlated with the advancement or delay in the expression of a set of genes that may be implicated in the maturation process. A detailed analysis of the transcription factors known to be involved in the regulation of fruit ripening identified a member of the MADS box family whose expression was lower in ARR, the early-ripening mutant, and higher in HER, the late-ripening mutant. The pattern of expression of this gene during the maturation period was basically contrary to those of the ethylene biosynthetic genes, SAM and ACC synthases and ACC oxidase. The gene was present in hemizygous dose in the early-ripening mutant. Conclusions: Our analysis provides new clues about the genetic control of fruit ripening in citrus and allowed the identification of a transcription factor that could be involved in the early phenotype. [ABSTRACT FROM AUTHOR]

MADS box transcription factors have been studied extensively in flowering plants but remain less studied in non-seed plants. MADS box is one such example of a gene which is prevalent across many classes of plants ranging from chlorophyta to embryophyta as well as fungi and animals. MADS box transcription factors are of two types, Type I and Type II. Type II transcription factors (TF) that consist of a MADS domain, I region, K domain, and C terminal domain are discussed in this review. The Type II/ MIKC class is widespread across charophytes and all major lineages of land plants but unknown in green and red algae. These transcription factors have been implicated in floral development in seed plants and thus the question arises, "What is their role in non-seed plants?" From the studies reviewed here it can be gathered that unlike seed plants, MIKCC genes in non-seed plants have roles in both gametophytic and sporophytic generations and contribute to the development of both vegetative and reproductive structures. On the other hand as previously observed in seed plants, MIKC* genes of non-seed plants have a conserved role during gametophyte development. With respect to evolution of MIKC genes in non-seed plants, the number of common ancestors is probably very few at each branch. The expansion of this gene family in seed plants and increased plant complexity seem to be correlated. As gradually the genomes of non-seed plants are becoming available it is worthwhile to gather the existing information about MADS box genes in non-seed plants. This review highlights various MIKC MADS box genes discovered so far in non-seed plants, their possible roles and an insight into their evolution. [ABSTRACT FROM AUTHOR]

Oxalate decarboxylase (OxDC), catalyzing the degradation of oxalic acid, is widely distributed in varieties of organisms. In this study, an oxalate decarboxylase gene from Bacillus subtilis strain BS-916, Bacisubin , was transformed into rice variety Nipponbare to generate transgenic rice with increased OxDC activity. Pathogenicity test revealed that the transgenic rice showed enhanced resistance to rice blast and sheath blight. Further RNA-seq analysis between Nipponbare WT (wild type) and transgenic rice identified 1764 DEGs (Differentially expressed genes) including 723 up-regulated unigenes and 1041 down-regulated unigenes. Five GO terms including single-organism process and oxidation-reduction process were significantly enriched in the up-regulated genes. Interestingly, five genes encoding glutaredoxin and one gene encoding MADS box were up- and down-regulated in the transgenic rice, respectively. Collectively, our study advances the understanding of OxDC in resistance to rice disease and its possible mechanisms. Our results also suggest that OxDC would be an effective antifungal protein preventing fungal infection in transgenic rice. [ABSTRACT FROM AUTHOR]

Saffron is grown for using its flower and red color stigma. This plant has many uses in the food industry, paints and medicine. Due to its high monetary worth, identification of genes involved in the flowering is very important. In order to better understand the molecular mechanisms involved in the onset of flowering, Gene and gene expression of Pistillata-Like MADS box (PIC2) were studied. The Gene sequences have high homology with other family members of the MADS-box family (one of the transcription factors control the expression of proteins flowers). In this research, the gene was studied using bioinformatics resources. Primers were designed for amplification of the gene and then the total DNA and RNA were extracted from the leaves of saffron. cDNA synthesis was performed by the reverse transcriptase enzyme and it was used as a template for amplification of PIC2 gene by PCR reaction. The reaction was amplified to a fragment with length 900 bp from cDNA and another fragment with length 2100 bp from genomic DNA. This gene encodes a protein that includes 210 amino acids. By analyzing the molecular structure of protein transcripts based on modeling of the gene homology, the spatial figure showed that they have a regular structure. [ABSTRACT FROM AUTHOR]

Fertilization in flowering plants requires a complex series of coordinated events involving interaction between the male and female gametophyte. We report here molecular data on one of the key events underpinning this process -- the death of the receptive synergid cell and the coincident bursting of the pollen tube inside the ovule to release the sperm. We show that two REM transcription factors, VALKYRIE (VAL) and VERDANDI (VDD), both targets of the ovule identity MADS-box complex SEEDSTICK-SEPALLATA3, interact to control the death of the receptive synergid cell. In vdd-1/+ mutants and VAL_RNAi lines, we find that GAMETOPHYTIC FACTOR 2(GFA2), which is required for synergid degeneration, is downregulated, whereas expression of FERONIA (FER) and MYB98, which are necessary for pollen tube attraction and perception, remain unaffected. We also demonstrate that the vdd-1/+ phenotype can be rescued by expressing VDD or GFA2 in the synergid cells. Taken together, our findings reveal that the death of the receptive synergid cell is essential for maintenance of the following generations, and that a complex comprising VDD and VAL regulates this event. [ABSTRACT FROM AUTHOR]

Polycomb Repressive Complex 2 ( PRC2) represses the transcriptional activity of target genes through trimethylation of lysine 27 of histone H3. The functions of plant PRC2 have been chiefly described in Arabidopsis, but specific functions in other plant species, especially cereals, are still largely unknown. Here we characterize mutants in the rice EMF2B gene, an ortholog of the Arabidopsis EMBRYONIC FLOWER2 ( EMF2) gene. Loss of EMF2B in rice results in complete sterility, and mutant flowers have severe floral organ defects and indeterminacy that resemble loss-of-function mutants in E-function floral organ specification genes. Transcriptome analysis identified the E-function genes Os MADS1, Os MADS6 and Os MADS34 as differentially expressed in the emf2b mutant compared with wild type. Os MADS1 and Os MADS6, known to be required for meristem determinacy in rice, have reduced expression in the emf2b mutant, whereas Os MADS34 which interacts genetically with Os MADS1 was ectopically expressed. Chromatin immunoprecipitation for H3K27me3 followed by quantitative (q) RT- PCR showed that all three genes are presumptive targets of PRC2 in the meristem. Therefore, in rice, and possibly other cereals, PRC2 appears to play a major role in floral meristem determinacy through modulation of the expression of E-function genes. [ABSTRACT FROM AUTHOR]

OsMADS29, a seed-specific transcription factor that affects grain filling and embryo development by regulating hormone homeostasis, requires homo- or heterodimerization with eleven other MADS proteins for its localization into the nucleus.OsMADS29 is a seed-specific MADS-box transcription factor that affects embryo development and grain filling by maintaining hormone homeostasis and degradation of cells in the nucellus and nucellar projection. Although it has a bipartite nuclear localization signal (NLS) sequence, the transiently expressed OsMADS29 monomer does not localize specifically in the nucleus. Dimerization of the monomers alters the intracellular localization fate of the resulting OsMADS29 homodimer, which then translocates into the nucleus. By generating domain-specific deletions/mutations, we show that two conserved amino acids (lysine23 and arginine24) in the NLS are important for nuclear localization of the OsMADS29 homodimer. Furthermore, the analyses involving interaction of OsMADS29 with 30 seed-expressed rice MADS proteins revealed 19 more MADS-box proteins, including five E-class proteins, which interacted with OsMADS29. Eleven of these complexes were observed to be localized in the nucleus. Deletion analysis revealed that the KC region (K-box and C-terminal domain) plays a pivotal role in homodimerization. These data suggest that the biological function of OsMADS29 may not only be regulated at the level of transcription and translation as reported earlier, but also at the post-translational level by way of the interaction between OsMADS29 monomers, and between OsMADS29 and other MADS-box proteins. [ABSTRACT FROM PUBLISHER]

The Ficus carica L. (Moraceae) tree belongs to one of the largest genera of angiosperms and bears a unique closed inflorescence structure. Ripe fresh figs are highly perishable and require delicate postharvest handling. Studying the pathways that lead to fig ripening may provide additional ways of extending their storage life. We selected four developmental stages of fig fruit for transcriptome sequencing and analysis to identify the major active metabolic pathways and transcription factors during fig fruit ripening. We found 12,751 unigenes, 93 % of which were homologous to at least one nonredundant database sequence, and 46,927 singletons, 39 % with a matching sequence from the nonredundant database. Differential activity related to photosynthesis, anthocyanin and volatile metabolism, cell wall and wax metabolism, cell expansion, transcription, DNA metabolism and organization was traced. In addition, ethylene-synthesis genes were identified. Finally, 516 unigenes encoding transcription factors were found which were active in the regulation of early and late ripening processes. Focusing on eight FcMADS-box transcription factors revealed three genes encoding members of the AGL2 (SEP) subfamily, which is closely associated with ripening regulation. This study provides expressed-gene dataset for multiple developmental stages of fig fruit ( F. carica), and analysis directed to ripening metabolism, control, and regulation. It provides a potential platform for further studies of this unique plant family and contributes to ripening process research in nonmodel systems. [ABSTRACT FROM AUTHOR]

One mutant transgenic line displaying homeotic conversion of sepals to petals with other phenotypic aberrations was selected and characterized at molecular level. The increased transcript level of gene encoding anthocyanidin synthase and petal specific class B genes, GLOBOSA and DEFECIENS in sepals of mutant line may be responsible for its homeotic conversion to petaloid organs. While characterizing this mutant line for locus identification, T-DNA was found to be inserted in 3′ untranslated region of promoter of class B MADS box gene, GLOBOSA. Here, CaMV 35S promoter of T-DNA might be deriving the expression of class B genes. [ABSTRACT FROM AUTHOR]

Rice MADS29 has recently been reported to cause programmed cell death of maternal tissues, the nucellus, and the nucellar projection during early stages of seed development. However, analyses involving OsMADS29 protein expression domains and characterization of OsMADS29 gain-of-function and knockdown phenotypes revealed novel aspects of its function in maintaining hormone homeostasis, which may have a role in the development of embryo and plastid differentiation and starch filling in endosperm cells. The MADS29 transcripts accumulated to high levels soon after fertilization; however, protein accumulation was found to be delayed by at least 4 days. Immunolocalization studies revealed that the protein accumulated initially in the dorsal-vascular trace and the outer layers of endosperm, and subsequently in the embryo and aleurone and subaleurone layers of the endosperm. Ectopic expression of MADS29 resulted in a severely dwarfed phenotype, exhibiting elevated levels of cytokinin, thereby suggesting that cytokinin biosynthesis pathway could be one of the major targets of OsMADS29. Overexpression of OsMADS29 in heterologous BY2 cells was found to mimic the effects of exogenous application of cytokinins that causes differentiation of proplastids to starch-containing amyloplasts and activation of genes involved in the starch biosynthesis pathway. Suppression of MADS29 expression by RNAi severely affected seed set. The surviving seeds were smaller in size, with developmental abnormalities in the embryo and reduced size of endosperm cells, which also contained loosely packed starch granules. Microarray analysis of overexpression and knockdown lines exhibited altered expression of genes involved in plastid biogenesis, starch biosynthesis, cytokinin signalling and biosynthesis. [ABSTRACT FROM PUBLISHER]

Transcriptional activation of the VERNALIZATION1 gene mediates the acceleration of flowering by prolonged cold (vernalization) in temperate cereals. This study examined the earliest stages of the transcriptional response of VRN1 to low temperatures. Time-course analyses, using a sensitive quantitative PCR assay, showed that in sprouting barley seedlings VRN1 transcripts begin to accumulate within 24 hours of the onset of cold. The kinetics of the initial transcriptional response of VRN1 to cold was similar to the cold-induced genes DEHYDRIN5 (DHN5) and COLD REGULATED 14B (COR14B), but occurred at lower levels compared to cold acclimation genes or the response to longer cold treatments. Temperatures between 15 and –2 °C induced expression of VRN1 within 24 hours, with a maximal response observed between 2 and –2 °C. Transcriptional induction was also observed in undifferentiated callus cells. There were significant increases in histone acetylation levels at the VRN1 locus in response to 24-hour cold treatment. Sodium butyrate, a histone deacetylation inhibitor, triggered an increase in histone acetylation at VRN1 chromatin and elevated VRN1 transcript levels. The transcriptional response of VRN1 to short-term cold treatment was examined in near-isogenic lines that have different VRN1 genotypes, showing that an allele of the barley VRN1 gene with an insertion in the first intron and high basal expression levels has a reduced transcriptional response to short term cold treatment. This study suggests that low-temperature induction of VRN1 is a cellular response to cold triggered by the same mechanisms that mediate low-temperature induction of cold acclimation genes. [ABSTRACT FROM AUTHOR]

BrAGL20 ( SOC1) containing MADS box, a floral integrator gene, was introduced into Brassica napus cv. 'Youngsan' by Agrobacterium-mediated transformation. Constitutively overexpressed BrAGL20 under the CaMV 35S promoter induced early flowering time compared to the wild-type. These phenotypes were stably inherited through generations T and T, regardless of planting season. The expression of the floral meristem identity genes LFY and AP1 seemed to appear rapidly in the shoot apex region of transgenic plants showing the early flowering time phenotype. These results suggest that overexpression of BrAGL20 can significantly affect the flowering time of B. napus, and regulation of floral integrator gene expression could be applied for adaptation of crops to local environments and climate changes. [ABSTRACT FROM AUTHOR]

Flowering plants utilize different floral structures to develop flesh tissue in fruits. Here we show that suppression of the homeologous SEPALLATA1/2-like genes MADS8 and MADS9 in the fleshy fruit apple ( Malus x domestica) leads to sepaloid petals and greatly reduced fruit flesh. Immunolabelling of cell-wall epitopes and differential staining showed that the developing hypanthium (from which the apple flesh develops) of MADS8/9-suppressed apple flowers lacks a tissue layer, and the remaining flesh tissue of fully developed apples has considerably smaller cells. From these observations, it is proposed that MADS8 and MADS9 control the development of discrete zones within the hypanthium tissue, and therefore fruit flesh, and also act as foundations for development of different floral organs. At fruit maturity, the MADS8/9-suppressed apples do not ripen in terms of both developmentally controlled ripening characters, such as starch degradation, and ethylene-modulated ripening traits. Transient assays suggest that, like the RIN gene in tomato, the MADS9 gene acts as a transcriptional activator of the ethylene biosynthesis enzyme, 1-aminocyclopropane-1-carboxylate (ACC) synthase 1. The existence of a single class of genes that regulate both flesh formation and ripening provides an evolutionary tool for controlling two critical aspects of fleshy fruit development. [ABSTRACT FROM AUTHOR]

Background Studying a process in a new species often relies on focusing our attention to a candidate gene, encoding a protein similar to one with a known function. Not all the choices seem to be prudent. Scope This Viewpoint includes an overview of issues that are encountered during research of candidate genes. Defining a match for a gene of interest, deciding whether variation in ESTs or RNAseq data for a certain transcript, represent more than one gene. The problem of incorrect annotation of genes due to incorrect in-silico splicing, is also mentioned. The author's humble opinion on how to deal with these issues is provided. Conclusions The vast amount of new sequence data provides us with great possibilities for giant leaps in our understanding. Still, we cannot afford to skip over the tedious steps required to confirm that we are indeed studying the correct gene, and try to be sure that the complex expression pattern we observe is not a composite of several genes. [ABSTRACT FROM AUTHOR]

The B-class of MADS box genes has been studied in a wide range of plant species, but has remained largely uncharacterized in legumes. Here we investigate the evolutionary fate of the duplicated AP3-like genes of a legume species. To obtain insight into the extent to which B-class MADS box gene functions are conserved or have diversified in legumes, we isolated and characterized the two members of the AP3 lineage in Medicago truncatula: MtNMH7 and MtTM6 ( euAP3 and paleoAP3 genes, respectively). A non-overlapping and complementary expression pattern of both genes was observed in petals and stamens. MtTM6 was expressed predominantly in the outer cell layers of both floral organs, and MtNMH7 in the inner cell layers of petals and stamens. Functional analyses by reverse genetics approaches (RNAi and Tnt1 mutagenesis) showed that the contribution of MtNMH7 to petal identity is more important than that of MtTM6, whereas MtTM6 plays a more important role in stamen identity than its paralog MtNMH7. Our results suggest that the M. truncatula AP3-like genes have undergone a functional specialization process associated with complete partitioning of gene expression patterns of the ancestral gene lineage. We provide information regarding the similarities and differences in petal and stamen development among core eudicots. [ABSTRACT FROM AUTHOR]

Interploidy crosses fail in many plant species due to abnormalities in endosperm development. In the inbreeding species Arabidopsis thaliana, both paternal and maternal excess interploidy crosses usually result in viable seed that exhibit parent-of-origin effects on endosperm development and final seed size. Paternal excess crosses result in extended proliferation of the endosperm and larger seeds, while conversely maternal excess crosses result in early endosperm cellularisation and smaller seeds. Investigations into the effect of parental gene dosage on seed development have revealed that MADS box transcription factors, particularly the AGAMOUS-like family, play important roles in controlling endosperm proliferation. The important crop genus Brassica contains self-incompatible outbreeding species and has a larger and more complex genome than the closely related Arabidopsis. Here we show that although Brassica oleracea displays strong parent-of-origin effects on seed development, triploid block due to lethal disruption of endosperm development was restricted to paternal excess, with maternal excess crosses yielding viable seed. In addition, transcriptome analyses of Brassica homologues of Arabidopsis genes linked to parent-of-origin effects revealed conservation of some mechanisms controlling aspects endosperm behaviour in the two species. However, there were also differences that may explain the failure of the paternal excess cross in B. oleracea. [ABSTRACT FROM AUTHOR]

MADS-box transcription factors are known to be involved in many important processes during plant growth and development. To date, few cucumber MADS-box genes and little tissue expression profiling have been reported. Recent completion of the cucumber whole-genome sequencing has allowed genome-wide analysis of the MADS-box gene family in cucumber as well as its comparison with other species. Here, we performed comprehensive analyses of the 43 cucumber MADS-box genes and compared them with those in Arabidopsis, poplar, and grapevine. The phylogenetic analysis showed that most cucumber members were comparable with those in other species, with the exception of AG members. At the same time, the three subfamilies FLC, AGL12, and Bs were absent in the cucumber genome. The conserved motif analysis revealed that most motifs outside the MADS domain were distributed only in specific groups. The analysis of chromosomal localization suggested that tandem duplication might contribute to the MADS-box gene expansion. Expression analysis revealed that 42 of 43 cucumber MADS-box members were expressed in multiple plant tissues, thereby implying their various roles in plants. [ABSTRACT FROM AUTHOR]

Although many models have been proposed that could lead to the maintenance of gene duplicates, the ways in which interacting gene duplicates influence each other’s evolution and function remain poorly understood. Here, we focus on duplication and loss of the B class MADS box transcription factor genes in the euasterids I and the ramifications of such changes on paralog evolution and their encoded functions. In core eudicots, the B class genes belong to two paralogous lineages whose products form obligate heterodimers. Based on comparative genomic and phylogenetic analyses, we show that five stepwise B class MADS box gene gain or loss events occurred during the radiation of the euasterids I within core eudicots. Gene loss in one sublineage was correlated with a deficit of other sublineage genes. We also show that the gain or loss of B class MADS box gene paralogs were associated with altered protein–protein interactions among the remaining copies. These altered protein interactions were correlated with asymmetric patterns of sequence diversification and selection, suggesting that compensatory changes were driving the evolution of such genes. Furthermore, these B class MADS box gene gain or loss events were associated with the evolutionary divergence of floral morphology in the euasterids I. Together, these observations point to a cooperative strategy by which gene networks evolve, with selection maintaining the overall logic of a network despite changes in individual components. [ABSTRACT FROM PUBLISHER]

A soybean MADS box gene Gm GAL2 ( Glycine max AGAMOUS Like 2), a homolog of AGL11/ STK, was investigated in transgenic Arabidopsis lines. Ectopic expression of Gm GAL2 in Arabidopsis enhanced flowering, under both long-day and short-day conditions, by promoting expression of key flowering genes, CONSTANS ( CO) and FLOWERING LOCUS T ( FT), and lowering expression of floral inhibiter FLOWERING LOCUS C ( FLC). Moreover, frequency of silique pod set was also lower in transgenic compared to control Arabidopsis plants. RT-PCR results revealed that Gm GAL2 was primarily expressed in the flowers and pods of soybean plants, Gm GAL2 expressed higher in SD than LD in soybean. [ABSTRACT FROM AUTHOR]

•The MADS box transcription factor family has long been identified as an important contributor to the control of floral development. It is often hypothesized that the evolution of floral development across angiosperms and within specific lineages may occur as a result of duplication, functional diversification, and changes in regulation of MADS box genes. Here we examine the role of GLOBOSA ( GLO) -like genes, members of the B-class MADS box gene lineage, in the evolution of floral development within the monocot order Zingiberales. •We assessed changes in perianth and stamen whorl morphology in a phylogenetic framework. We identified GLO homologs ( ZinGLO1-4) from 50 Zingiberales species and investigated the evolution of this gene lineage. Expression of two GLO homologs was assessed in Costus spicatus and Musa basjoo. •Based on the phylogenetic data and expression results, we propose several family-specific losses and gains of GLO homologs that appear to be associated with key morphological changes. The GLO-like gene lineage has diversified concomitant with the evolution of the dimorphic perianth and the staminodial labellum. •Duplications and expression divergence within the GLO-like gene lineage may have played a role in floral diversification in the Zingiberales. [ABSTRACT FROM AUTHOR]

AGAMOUS clade genes encode MADS box transcription factors that have been shown to play critical roles in many aspects of flower and fruit development in angiosperms. Tomato possesses two representatives of this lineage, TOMATO AGAMOUS (TAG1) and TOMATO AGAMOUS-LIKE1 (TAGL1), allowing for an analysis of diversification of function after gene duplication. Using RNAi (RNA interference) silencing, transgenic tomato lines that specifically down-regulate either TAGL1 or TAG1 transcript accumulation have been produced. TAGL1 RNAi lines show no defects in stamen or carpel identity, but show defects in fruit ripening. In contrast TAG1 RNAi lines show defects in stamen and carpel development. In addition TAG1 RNAi lines produce red ripe fruit, although they are defective in determinacy and produce ectopic internal fruit structures. e2814, an EMS- (ethyl methane sulphonate) induced mutation that is temperature sensitive and produces fruit phenotypes similar to that of TAG1 RNAi lines, was also characterized. Neither TAG1 nor TAGL1 expression is disrupted in the e2814 mutant, suggesting that the gene corresponding to the e2814 mutant represents a distinct locus that is likely to be functionally downstream of TAG1 and TAGL1. Based on these analyses, possible modes by which these gene duplicates have diversified in terms of their functions and regulatory roles are discussed. [ABSTRACT FROM PUBLISHER]

The nucleotide sequences of regulatory elements from homologous genes can be strongly divergent. Phylogenetic footprinting, a comparative analysis of noncoding regions, can detect putative transcription factor binding sites (TFBSs) shared among the regulatory regions of 2 or more homologous genes. These conserved motifs have the potential to serve the same regulatory function in distantly related taxa. We isolated the 5′-noncoding region of the OrcPI gene, a MADS-box transcription factor involved in flower development in Orchis italica, using the thermal asymmetric interlaced polymerase chain reaction technique. This region (comprising 1352 bp) induced transient β-glucuronidase expression in the petal tissue of white Rosa hybrida flowers and represents the 5′-regulatory sequence of the OrcPI gene. Phylogenetic footprinting analysis detected conserved regions within the 5′-regulatory sequence of OrcPI and the homologous regions of Oryza sativa, Lilium regale, and Arabidopsis thaliana. Some of these sequences are known TFBSs described in databases of plant regulatory elements. Nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the following accession numbers: AF198055 promoter region of the PISTILLATA (PI) gene of A. thaliana; AB094985 cDNA of OrcPI (PI/GLOBOSA [PI/GLO] homologue) of O. italica; AB378089 5′-regulatory region of the OrcPI gene of O. italica; AP008211 putative promoter region of OSMADS2 (PI/GLO homologue) of O. sativa; AP008207 putative promoter region of OSMADS4 (PI/GLO homologue) of O. sativa; and AB158292 putative promoter region of the PI/GLO homologue of L. regale. [ABSTRACT FROM PUBLISHER]

During the initial stages of flower development, floral meristems increase in size without the formation of floral organs. When a critical meristem size is reached, the floral meristem begins to develop the floral organs. The first stages of flower development are characterized by the expression of genes such as APETALA 1 ( AP1), CAULIFLOWER ( CAL), AGAMOUS-LIKE 24 ( AGL24) and SHORT VEGETATIVE PHASE ( SVP). We have shown that AP1, AGL24 and SVP act redundantly to control the identity of the floral meristem and to repress expression of class B, C and E genes. Recently, it was shown that class E gene repression was direct and established by two independent pathways. We show here that repression of class B and C genes is also directly established by a co-repressor complex that comprises LEUNIG (LUG), SEUSS (SEU) and the MADS box dimers AP1–AGL24 and AP1–SVP. Furthermore, we show that the distantly related SUPPRESSOR OF OVEREXPRESSION OF CO 1 ( SOC1) MADS box gene can complement for the loss of AGL24 and SVP activity; however, under normal conditions, this transcription factor does not play a role during the early stages of flower development. [ABSTRACT FROM AUTHOR]

Expressed sequence tags (ESTs) for the basal angiosperms Amborella trichopoda (Amborellaceae) and the water lily Nuphar advena (Nymphaeaceae) have proven valuable in identification of gene pairs to study the timing of duplication events relative to the most recent common ancestor (MRCA) of all extant angiosperms. Here we discuss how ESTs for these taxa are also useful for deducing gene families that were present in the MRCA of all flowering plants. For example, 4,572 gene clusters identified in an analysis of the rice and Arabidopsis proteomes contained putative orthologs of Amborella or Nuphar. Homologs of many developmentally important genes were identified from Amborella or Nuphar in these gene clusters. This number of ancestral genes is expected to increase as the number of Amborella and water lily ESTs increases. Genes found unduplicated in the rice and Arabidopsis genomes may be especially useful for phylogenetic analyses including diverse angiosperm lineages. We identify 595 of these single copy genes with putative orthologs in Amborella or Nuphar. Phylogenetic analysis of one of these nuclear single-copy genes encoding the enzyme carboxymethylenebutenolidase yields a topology that places Amborella and Nuphar as the sisters to all other extant lineages of angiosperms and is generally consistent with current angiosperm phylogenies based mainly on chloroplast, mitochondrial, and nuclear ribosomal sequences. [ABSTRACT FROM AUTHOR]

SEPALLATA ( SEP) MADS box genes play essential and diverse roles in reproductive organ development. To investigate the SEP gene function in peach we isolated three SEP-like genes, PrpMADS2, PrpMADS5, and PrpMADS7, which belong to distinct SEP gene clades. They appeared as single copy genes in the peach genome and were found to preferentially express in flowers and fruits. Arabidopsis transformants expressing 35S: PrpMADS2 were indistinguishable from wild-type plants. Overexpression of PrpMADS5 led to earlier flowering. Through chimeric repressor silencing technology, PrpMADS5 was found to function in floral organ development. Expression of PrpMADS7 in Arabidopsis caused a dramatic attenuation of both juvenile and adult growth phases and, in severely affected plants, it led to flower formation immediately after the embryonic phase. Two microsatellite markers were developed for PrpMADS2 and PrpMADS5 and assigned to the genetic linkage groups 5 and 1, respectively. PrpMADS7, previously identified as PrpAGL2, and PrpMADS5 were identified as potential loci to modify the flowering time and floral organs in Prunus species. Moreover, our results showed the diversification of SEP genes in peach. [ABSTRACT FROM AUTHOR]

The RIN gene encodes a putative MADS box transcription factor that controls tomato fruit ripening, and its ripening inhibitor ( rin) mutation yields non-ripening fruit. In this study, the molecular properties of RIN and the rin mutant protein were clarified. The results revealed that the RIN protein accumulates in ripening fruit specifically and is localized in the nucleus of the cell. In vitro studies revealed that RIN forms a stable homodimer that binds to MADS domain-specific DNA sites. Analysis of binding site selection experiments revealed that the consensus binding sites of RIN highly resemble those of the SEPALLATA (SEP) proteins, which are Arabidopsis MADS box proteins that control the identity of floral organs . RIN exhibited a transcription-activating function similar to that exhibited by the SEP proteins. These results indicate that RIN exhibits similar molecular functions to SEP proteins although they play distinctly different biological roles. In vivo assays revealed that RIN binds to the cis-element of LeACS2. Our results also revealed that the rin mutant protein accumulates in the mutant fruit and exhibits a DNA-binding activity similar to that exhibited by the wild-type protein, but has lost its transcription-activating function, which in turn would inhibit ripening in mutant fruit. [ABSTRACT FROM AUTHOR]

A Petunia inflata isolate with a novel phenotype of a purple corolla limb with green corolla segments (GCS) was characterized. The GCS have stomata and trichomes on the adaxial side, and resemble calyx segments in epidermal morphology. The GCS phenotype was inherited in a recessive manner. In the GCS plant, a novel inhibitor/defective spm-like transposable element ( dPifTp1) was inserted in the second intron of the Floral Binding Protein 2 ( FBP2) gene. The sequence of the resulting transcript contained five silent mutations as compared the corresponding open reading frame of P. × hybrida FBP2 mRNA. The GCS phenotype co-segregated with an FBP2 fragment containing a dPifTp1 insertion. The transcript level of the FBP2 gene in GCS flowers was markedly lower than that in wild-type (WT) flowers, suggesting that partially inhibited FBP2 gene expression caused the morphogenesis of calyx-like tissue in the corolla segments of GCS flowers. Gene expression pattern analysis using a full-length Petunia floral cDNA microarray indicated that some photosynthesis-related genes were expressed at significantly higher levels in the GCS of GCS flowers, but the mRNA levels of most other genes in the GCS were similar to those in the WT corolla. Taken together, these data suggest that the partial loss of FBP2 expression does not shift global gene expression in the corolla segments of the GCS flower toward that of calyx, even though calyx-like morphogenesis was established in the corolla segments. [ABSTRACT FROM AUTHOR]

Previously an AGAMOUS gene homologue PpMADS4 and a FRUITFULL gene homologue PpMADS6 were isolated from peach (Prunus persica), and both genes were shown to express in the developing floral and fruits. To gain insight into their function, the two genes were constitutively expressed in Arabidopsis thaliana and their effects on plant growth and floral organ development were studied in this work. The transgenic plants all displayed early flowering and conversion of inflorescence to floral meristem. However, the two genes had different effects on the floral organ structures in A. thaliana. The transgenic plants overexpressing PpMADS4 displayed homeotic conversion of floral organs, and particularly the perianth abscission was inhibited. The plants overexpressing PpMADS6 showed early flowering, produced higher number of carpels, petals, and stamens than nontransgenic plants, and pod shatter was prevented; significantly, the transgenic plants yielded more than one siliques from a single flower. A SSR molecular marker was developed for PpMADS4, and it was then assigned into the G5 linkage group of Prunus sp. Both PpMADS4 and PpMADS6 genes were located at the same region in the G5 linkage group. Our results showed the potential application of these two MADS box genes for crop and fruit tree improvement. [ABSTRACT FROM AUTHOR]

Duplicated APETALA1/FRUITFULL ( AP1/FUL) genes show distinct but overlapping patterns of expression within rice ( Oryza sativa) and within ryegrass ( Lolium temulentum), suggesting discrete functional roles in the transition to flowering, specification of spikelet meristem identity, and specification of floral organ identity. In this study, we analyzed the expression of the AP1/FUL paralogues FUL1 and FUL2 across phylogenetically disparate grasses to test hypotheses of gene function. In combination with other studies, our data support similar roles for both genes in spikelet meristem identity, a general role for FUL1 in floral organ identity, and a more specific role for FUL2 in outer floral whorl identity. In contrast to Arabidopsis AP1/FUL genes, expression of FUL1 and FUL2 is consistent with an early role in the transition to flowering. In general, FUL1 has a wider expression pattern in all spikelet organs than FUL2, but both genes are expressed in all spikelet organs in some cereals. FUL1 and FUL2 appear to have multiple redundant functions in early inflorescence development. We hypothesize that sub-functionalization of FUL2 and interaction of FUL2 with LHS1 could specify lemma and palea identity in the grass floret. [ABSTRACT FROM AUTHOR]

In wheat, VRN1/TaVRN1 and VRN2/TaVRN2 determine the growth habit and flowering time. In addition, the MADS box transcription factor VEGETATIVE TO REPRODUCTIVE TRANSITION 2 (TaVRT2) is also associated with the vernalization response in a manner similar to TaVRN2. However, the molecular relationship between these three genes and their products is unknown. Using transient expression assays in Nicotiana benthamiana, we show that TaVRT2 acts as a repressor of TaVRN1 transcription. TaVRT2 binds the CArG motif in the TaVRN1 promoter and represses its activity in vivo. In contrast, TaVRN2 does not bind the TaVRN1 promoter and has no direct effect on its activity, but it can enhance the repression effect of TaVRT2. This suggests that a repressor complex regulates the expression of TaVRN1. In winter wheat, TaVRT2, TaVRN2 and TaVRN1 transcripts accumulate in the shoot apical meristem and young leaves, and temporal expression is consistent with TaVRT2 and TaVRN2 being repressors of floral transition, whereas TaVRN1 is an activator. Non-vernalized spring wheat grown under a short-day photoperiod accumulates TaVRT2 and shows a delay in flowering, suggesting that TaVRT2 is regulated independently by photoperiod and low temperature. The data presented suggest that TaVRT2, in association with TaVRN2, represses the transcription of TaVRN1. [ABSTRACT FROM AUTHOR]

The developmental roles of AGL15 and AGL18, members of the AGL15-like clade of MADS domain regulatory factors, have not been defined previously. Analysis of transgenic Arabidopsis plants showed that overexpression of AGL18 produces the same phenotypic changes as overexpression of AGL15, and the two genes have partially overlapping expression patterns. Functional redundancy was confirmed through analysis of loss-of-function mutants. agl15 agl18 double mutants, but not single mutants, flower early under non-inductive conditions, indicating that AGL15 and AGL18 act in a redundant fashion as repressors of the floral transition. Further genetic analyses and expression studies were used to examine the relationship between AGL15 and AGL18 activity and other regulators of the floral transition. AGL15 and AGL18 act upstream of the floral integrator FT, and a combination of agl15 and agl18 mutations partially suppresses defects in the photoperiod pathway. agl15 agl18 mutations show an additive relationship with mutations in genes encoding other MADS domain floral repressors, and further acceleration of flowering is seen in triple and quadruple mutants under both inductive and non-inductive conditions. Thus, flowering time is determined by the additive effect of multiple MADS domain floral repressors, with important contributions from AGL15 and AGL18. [ABSTRACT FROM AUTHOR]

Tomato (Solanum lycopersicum, formerly Lycopersicon esculentum) cv. VFNT Cherry sepals, when cultured in vitro between 16 °C and 22 °C, change their genetic programme to that of ripening fruit. Previously regulation of a number of transcription factors and a putative G-protein-coupled receptor that may be involved in tomato fruit ripening and cool-temperature sepal morphogenesis had been revealed. Many of those genes such as TAG1, TM4, TM6, AP2-like (LeAP2FR), YABBY2-like (LeYAB2), and LeCOR413-PM1 have not been investigated for ethylene regulation. Ethylene-independent, regulated transcripts may be part of an early signalling process induced or de-repressed by cool temperature that causes a switch in the genetic programme of the sepals. In this paper, ethylene regulation of a number of these and other putative signalling factors are investigated during cool-temperature-induced sepal morphogenesis. 1-Methylcyclopropene was used to block ethylene-induced gene expression by interrupting the ethylene signal transduction pathway that occurs in ripening tomato fruits and presumably in ripening sepals. Transcripts of several putative transcription factors previously shown to be up-regulated during cool-temperature-induced sepal morphogenesis (TAG1, TM4, LeAP2FR) were only slightly or not induced in 1-methylcyclopropene-treated sepals, indicating either direct or indirect ethylene regulation. Two genes, VAHOX1, a homeobox domain leucine-zipper-encoding gene, and LeYAB2, a putative zinc-finger transcription factor-encoding gene, increased in treated and untreated sepals indicating regulation by cool temperatures independently of ethylene. [ABSTRACT FROM PUBLISHER]

In order to study the molecular regulation of flower development in the monoecious species oil palm (Elaeis guineensis), cDNAs of 12 MADS box genes from this plant belonging to seven distinct subfamilies were previously isolated and characterized. Here studies carried out on five of these genes, each likely to be involved in floral morphogenesis: EgSQUA1 (SQUAMOSA subfamily); EgAGL2-1 (AGL2 subfamily); EgGLO2 (GLOBOSA subfamily); EgDEF1 (DEFICIENS subfamily); and EgAG2 (AGAMOUS subfamily), are described. In order to determine where and when in the plant these genes are likely to function, their spatial and temporal patterns of expression were studied during the development of male and female inflorescences, either of normal phenotype or displaying a homeotic flowering abnormality known as mantled. In parallel, the phenotypic effects of ectopically expressing these genes in transgenic Arabidopsis thaliana plants were analysed. The data suggest a broad conservation of floral homeotic gene functions between oil palm and previously described model species, although a few minor variations in the zones of activity of certain genes cannot be excluded. The data also indicate distinct molecular identities for the morphologically similar floral organs of whorls 1 and 2. They also reveal reduced expression of putative B, C/D, and E class genes in mantled flowers, which undergo a homeotic transformation comparable to B class mutants of model species. [ABSTRACT FROM PUBLISHER]

Flowering plants go through several phases between regular stem growth and the actual production of flower parts. The stepwise conversion of vegetative into inflorescence and floral meristems is usually unidirectional, but under certain environmental or genetic conditions, meristems can revert to an earlier developmental identity. Vegetative meristems are typically indeterminate, producing organs continuously, whereas flower meristems are determinate, shutting down their growth after reproductive organs are initiated. Inflorescence meristems can show either pattern. Flower and inflorescence development have been investigated in Gerbera hybrida, an ornamental plant in the sunflower family, Asteraceae. Unlike the common model species used to study flower development, Gerbera inflorescences bear a fixed number of flowers, and the architecture of the flowers differ in that Gerbera ovaries are inferior (borne below the perianth). This architectural difference has been exploited to show that floral meristem determinacy and identity are spatially and genetically distinct in Gerbera, and we have shown that a single SEPALLATA-like MADS domain factor controls both flower and inflorescence meristem fate in the plant. Although these phenomena have not been directly observed in Arabidopsis, the integrative role of the SEPALLATA function in reproductive meristem development may be general for all flowering plants. [ABSTRACT FROM AUTHOR]

Unlike monopodial plants, in which flowering terminates growth of a shoot, plants exhibiting sympodial shoot architecture maintain the potential for indeterminate growth even after converting to floral development. This vegetative indeterminacy is conferred by a special type of axillary meristem, the sympodial meristem, which exhibits precocious but determinate growth. The reiterative formation of sympodial meristems as the plant grows results in a shoot composed of a series of modules, each consisting of a limited number of vegetative nodes and terminated by a flower or inflorescence. To determine how sympodial meristems differ from other shoot meristems, we examined interactions between mutations that affect various shoot meristem types in tomato ( Lycopersicon esculentum Mill.). Analysis of double mutant combinations of jointless, lateral suppressor, self-pruning, blind, and anantha showed that sympodial meristems share regulatory features with inflorescence meristems. Genetic studies on the jointless mutation implicated this gene in suppressing sympodial meristem fate in the inflorescence. As this mutation has a second phenotype, the elimination of the pedicel abscission zone, we examined the expression pattern of JOINTLESS to test whether pedicel development is involved in directing shoot architecture. We found that this MADS box gene is expressed in a variety of shoot meristems, including inflorescence, floral, sympodial, and axillary meristems, as well as in early staged floral organs, in sporogenous tissues of anthers, and in ovules. Lack of expression in developing pedicels indicates abscission zone development does not rely on JOINTLESS transcription in the differentiating cells. We conclude that the primary role of JOINTLESS is to suppress sympodial meristem identity in inflorescence meristems. [ABSTRACT FROM AUTHOR]