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Abstract Background The cotton whitefly (Bemisia tabaci) is a major global pest, causing significant crop damage through viral infestation and feeding. Traditional B. tabaci recognition relies on human eyes, which requires a large amount of work and high labor costs. The pests overlapping generations, high reproductive capacity, small size, and migratory behavior present challenges for the real-time monitoring and early warning systems. This study aims to develop an efficient, high-throughput automated system for detection of the cotton whiteflies. In this work, a novel tool for cotton whitefly fast identification and quantification was developed based on deep learning-based model. This approach enhances the effectiveness of B. tabaci control by facilitating earlier detection of its establishment in cotton, thereby allowing for a quicker implementation of management strategies. Results We compiled a dataset of 1200 annotated images of whiteflies on cotton leaves, augmented using techniques like flipping and rotation. We modified the YOLO v8s model by replacing the C2f module with the Swin-Transformer and introducing a P2 structure in the Head, achieving a precision of 0.87, mAP50 of 0.92, and F1 score of 0.88 through ablation studies. Additionally, we employed SAHI for image preprocessing and integrated the whitefly detection algorithm on a Raspberry Pi, and developed a GUI-based visual interface. Our preliminary analysis revealed a higher density of whiteflies on cotton leaves in the afternoon and the middle-top, middle, and middle-down plant sections. Conclusion Utilizing the enhanced YOLO v8s deep learning model, we have achieved precise detection and counting of whiteflies, enabling its application on hardware devices like the Raspberry Pi. This approach is highly suitable for research requiring accurate quantification of cotton whiteflies, including phenotypic analyses. Future work will focus on deploying such equipment in large fields to manage whitefly infestations.

Accurately quantifying flora and their respective anatomical structures within natural ecosystems is paramount for both botanical breeders and agricultural cultivators. For breeders, precise plant enumeration during the flowering phase is instrumental in discriminating genotypes exhibiting heightened flowering frequencies, while for growers, such data inform potential crop rotation strategies. Moreover, the quantification of specific plant components, such as flowers, can offer prognostic insights into the potential yield variances among different genotypes, thereby facilitating informed decisions pertaining to production levels. The overarching aim of the present investigation is to explore the capabilities of a neural network termed GhP2-YOLO, predicated on advanced deep learning techniques and multi-target tracking algorithms, specifically tailored for the enumeration of rapeseed flower buds and blossoms from recorded video frames. Building upon the foundation of the renowned object detection model YOLO v8, this network integrates a specialized P2 detection head and the Ghost module to augment the model’s capacity for detecting diminutive targets with lower resolutions. This modification not only renders the model more adept at target identification but also renders it more lightweight and less computationally intensive. The optimal iteration of GhP2-YOLOm demonstrated exceptional accuracy in quantifying rapeseed flower samples, showcasing an impressive mean average precision at 50% intersection over union metric surpassing 95%. Leveraging the virtues of StrongSORT, the subsequent tracking of rapeseed flower buds and blossom patterns within the video dataset was adeptly realized. By selecting 20 video segments for comparative analysis between manual and automated counts of rapeseed flowers, buds, and the overall target count, a robust correlation was evidenced, with R-squared coefficients measuring 0.9719, 0.986, and 0.9753, respectively. Conclusively, a user-friendly “Rapeseed flower detection” system was developed utilizing a GUI and PyQt5 interface, facilitating the visualization of rapeseed flowers and buds. This system holds promising utility in field surveillance apparatus, enabling agriculturalists to monitor the developmental progress of rapeseed flowers in real time. This innovative study introduces automated tracking and tallying methodologies within video footage, positioning deep convolutional neural networks and multi-target tracking protocols as invaluable assets in the realms of botanical research and agricultural administration.

The paper mulberry is a commonly found tree species with a long history of cultivation. It also serves as a crucial case study for understanding how woody plants adapt to low temperatures. Under cold treatment, we observed a substantial number of alternative splicing (AS) genes, showcasing the intricate landscape of AS events. We have detected all seven types of AS events, with the alternative 3′ splice site (A3) having the most. We observed that many genes that underwent differential AS were significantly enriched in starch and sucrose metabolism and circadian rhythm pathways. Moreover, a considerable proportion of differentially spliced genes (DSGs) also showed differential expression, with 20.38% and 25.65% under 12 h and 24 h cold treatments, respectively. This suggests a coordinated regulation between gene AS and expression, playing a pivotal role in the paper mulberry’s adaptation to cold stress. We further investigated the regulatory mechanisms of AS, identifying 41 serine/arginine-rich (SR) splicing factors, among which 11 showed differential expression under cold treatment, while 29 underwent alternative splicing. Additionally, genes undergoing AS displayed significantly higher DNA methylation levels under cold stress, while normal splicing (non-AS) genes exhibited relatively lower methylation levels. These findings suggest that methylation may play an important role in governing gene AS. Finally, our research will provide useful information on the role of AS in the cold acclimation tolerance of the paper mulberry.

Rapeseed is a significant oil crop, and the size and length of its pods affect its productivity. However, manually counting the number of rapeseed pods and measuring the length, width, and area of the pod takes time and effort, especially when there are hundreds of rapeseed resources to be assessed. This work created two state-of-the-art deep learning-based methods to identify rapeseed pods and related pod attributes, which are then implemented in rapeseed pots to improve the accuracy of the rapeseed yield estimate. One of these methods is YOLO v8, and the other is the two-stage model Mask R-CNN based on the framework Detectron2. The YOLO v8n model and the Mask R-CNN model with a Resnet101 backbone in Detectron2 both achieve precision rates exceeding 90%. The recognition results demonstrated that both models perform well when graphic images of rapeseed pods are segmented. In light of this, we developed a coin-based approach for estimating the size of rapeseed pods and tested it on a test dataset made up of nine different species of Brassica napus and one of Brassica campestris L. The correlation coefficients between manual measurement and machine vision measurement of length and width were calculated using statistical methods. The length regression coefficient of both methods was 0.991, and the width regression coefficient was 0.989. In conclusion, for the first time, we utilized deep learning techniques to identify the characteristics of rapeseed pods while concurrently establishing a dataset for rapeseed pods. Our suggested approaches were successful in segmenting and counting rapeseed pods precisely. Our approach offers breeders an effective strategy for digitally analyzing phenotypes and automating the identification and screening process, not only in rapeseed germplasm resources but also in leguminous plants, like soybeans that possess pods.

Cotton is a valuable cash crop in many countries. Cotton fiber is a trichome that develops from a single epidermal cell and serves as an excellent model for understanding cell differentiation and other life processes. Alternative splicing (AS) of genes is a common post-transcriptional regulatory process in plants that is essential for plant growth and development. The process of AS during cotton fiber formation, on the other hand, is mainly unknown. A substantial number of multi-exon genes were discovered to be alternatively spliced during cotton fiber formation in this study, accounting for 23.31% of the total number of genes in Gossypium hirsutum. Retention intron (RI) is not necessarily the most common AS type, indicating that AS genes and processes during fiber development are very temporal and tissue-specific. When compared to fiber samples, AS is more prevalent at the fiber initiation stages and in the ovule, indicating that development stages and tissues use different AS strategies. Genes involved in fiber development have gone through stage-specific AS, demonstrating that AS regulates cotton fiber development. Furthermore, AS can be regulated by trans-regulation elements such as splicing factor and cis-regulation elements such as gene length, exon numbers, and GC content, particularly at exon–intron junction sites. Our findings also suggest that increased DNA methylation may aid in the efficiency of AS, and that gene body methylation is key in AS control. Finally, our research will provide useful information about the roles of AS during the cotton fiber development process.

Abstract Background Cotton stem trichomes and seed fibers are each single celled structures formed by protrusions of epidermal cells, and were found sharing the overlapping molecular mechanism. Compared with fibers, cotton stem trichomes are more easily observed, but the molecular mechanisms underlying their development are still poorly understood. Results In this study, Gossypium hirsutum (Gh) and G. barbadense (Gb) were found to differ greatly in percentages of varieties/accessions with glabrous stems and in trichome density, length, and number per trichopore. Gh varieties normally had long singular and clustered trichomes, while Gb varieties had short clustered trichomes. Genetic mapping using five F2 populations from crosses between glabrous varieties and those with different types of stem trichomes revealed that much variation among stem trichome phenotypes could be accounted for by different combinations of genes/alleles on Chr. 06 and Chr. 24. The twenty- six F1 generations from crosses between varieties with different types of trichomes had varied phenotypes, further suggesting that the trichomes of tetraploid cotton were controlled by different genes/alleles. Compared to modern varieties, a greater proportion of Gh wild accessions were glabrous or had shorter and denser trichomes; whereas a smaller proportion of Gb primitive accessions had glabrous stems. A close correlation between fuzz fiber number and stem trichome density was observed in both Gh and Gb primitive accessions and modern varieties. Conclusion Based on these findings, we hypothesize that stem trichomes evolved in parallel with seed fibers during the domestication of cultivated tetraploid cotton. In addition, the current results illustrated that stem trichome can be used as a morphological index of fiber quality in cotton conventional breeding.

To improve our understanding of the mechanism of maize seed germination under deep sowing, transcriptome sequencing and physiological metabolism analyses were performed using B73 embryos separated from ungerminated seeds (UG) or seeds germinated for 2 d at a depth of 2 cm (normal sowing, NS) or 20 cm (deep sowing, DS). Gene ontology (GO) analysis indicated that “response to oxidative stress” and “monolayer-surrounded lipid storage body” were the most significant GO terms in up- and down-regulated differentially expressed genes (DEGs) of DS. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis suggested that “phenylpropanoid biosynthesis” and “starch and sucrose metabolism” were critical processes in maize seed germination under deep-sowing conditions. Consistent with DEGs, the activities of superoxide dismutase, catalase, peroxidases and α-amylase, as well as the contents of gibberellin 4, indole acetic acid, zeatin and abscisic acid were significantly increased, while the jasmonic-acid level was dramatically reduced under deep-sowing stress. The expressions of six candidate genes were more significantly upregulated in B73 (deep-sowing-tolerant) than in Mo17 (deep-sowing-sensitive) at 20 cm sowing depth. These findings enrich our knowledge of the key biochemical pathways and genes regulating maize seed germination under deep-sowing conditions, which may help in the breeding of varieties tolerant to deep sowing.

Abstract Background MADS-box genes encode a large family of transcription factors that play significant roles in plant growth and development. Bamboo is an important non-timber forest product worldwide, but previous studies on the moso bamboo (Phyllostachys edulis) MADS-box gene family were not accurate nor sufficiently detailed. Results Here, a complete genome-wide identification and characterization of the MADS-box genes in moso bamboo was conducted. There was an unusual lack of type-I MADS-box genes in the bamboo genome database (http://202.127.18.221/bamboo/index.php), and some of the PeMADS sequences are fragmented and/or inaccurate. We performed several bioinformatics techniques to obtain more precise sequences using transcriptome assembly. In total, 42 MADS-box genes, including six new type-I MADS-box genes, were identified in bamboo, and their structures, phylogenetic relationships, predicted conserved motifs and promoter cis-elements were systematically investigated. An expression analysis of the bamboo MADS-box genes in floral organs and leaves revealed that several key members are involved in bamboo inflorescence development, like their orthologous genes in Oryza. The ectopic overexpression of one MADS-box gene, PeMADS5, in Arabidopsis triggered an earlier flowering time and the development of an aberrant flower phenotype, suggesting that PeMADS5 acts as a floral activator and is involved in bamboo flowering. Conclusion We produced the most comprehensive information on MADS-box genes in moso bamboo. Additionally, a critical PeMADS gene (PeMADS5) responsible for the transition from vegetative to reproductive growth was identified and shown to be related to bamboo floral development.

Bamboo is one of the most important non-timber forest resources worldwide. It has considerable economic value and unique flowering characteristics. The long juvenile phase in bamboo and unpredictable flowering time limit breeding and genetic improvement and seriously affect the productivity and application of bamboo forests. Members of SQUA-like subfamily genes play an essential role in controlling flowering time and floral organ identity. A comprehensive study was conducted to explain the functions of five SQUA-like subfamily genes in Phyllostachys edulis. Expression analysis revealed that all PeSQUAs have higher transcript levels in the reproductive period than in the juvenile phase. However, PeSQUAs showed divergent expression patterns during inflorescence development. The protein–protein interaction (PPI) patterns among PeSQUAs and other MADS-box members were analyzed by yeast two-hybrid (Y2H) experiments. Consistent with amino acid sequence similarity and phylogenetic analysis, the PPI patterns clustered into two groups. PeMADS2, 13, and 41 interacted with multiple PeMADS proteins, whereas PeMADS3 and 28 hardly interacted with other proteins. Based on our results, PeSQUA might possess different functions by forming protein complexes with other MADS-box proteins at different flowering stages. Furthermore, we chose PeMADS2 for functional analysis. Ectopic expression of PeMADS2 in Arabidopsis and rice caused early flowering, and abnormal phenotype was observed in transgenic Arabidopsis lines. RNA-seq analysis indicated that PeMADS2 integrated multiple pathways regulating floral transition to trigger early flowering time in rice. This function might be due to the interaction between PeMADS2 and homologous in rice. Therefore, we concluded that the five SQUA-like genes showed functional conservation and divergence based on sequence differences and were involved in floral transitions by forming protein complexes in P. edulis. The MADS-box protein complex model obtained in the current study will provide crucial insights into the molecular mechanisms of bamboo’s unique flowering characteristics.

Dynamic remodeling of the actin cytoskeleton plays a central role in the elongation of cotton fibers, which are the most important natural fibers in the global textile industry. Here, a high-resolution mapping approach combined with comparative sequencing and a transgenic method revealed that a G65V substitution in the cotton actin Gh_D04G0865 (GhACT17D in the wild-type) is responsible for the Gossypium hirsutum Ligon lintless-1 (Li1) mutant (GhACT17DM). In the mutant GhACT17DM from Li1 plant, Gly65 is substituted with valine on the lip of the nucleotide-binding domain of GhACT17D, which probably affects the polymerization of F-actin. Over-expression of GhACT17DM, but not GhACT17D, driven by either a CaMV35 promoter or a fiber-specific promoter in cotton produced a Li1-like phenotype. Compared with the wild-type control, actin filaments in Li1 fibers showed higher growth and shrinkage rates, decreased filament skewness and parallelness, and increased filament density. Taken together, our results indicate that the incorporation of GhACT17DM during actin polymerization disrupts the establishment and dynamics of the actin cytoskeleton, resulting in defective fiber elongation and the overall dwarf and twisted phenotype of the Li1 mutant.

Wheat heading date is an important agronomic trait determining maturation time and yield. A set of common wheat (Triticum aestivum var. Chinese Spring; CS)-wild emmer (T. turgidum L. subsp. dicoccoides (TDIC)) chromosome arm substitution lines (CASLs) was used to identify and allocate QTLs conferring late or early spike emergence by examining heading date. Genetic loci accelerating heading were found on TDIC chromosome arms 3AL and 7BS, while loci delaying heading were located on 4AL and 2BS. To map QTLs conferring late heading on 2BS, F2 populations derived from two cross combinations of CASL2BS × CS and CASL3AL × CASL2BS were developed and each planted at two times, constituting four F2 mapping populations. Heading date varied continuously among individuals of these four populations, suggesting quantitative characteristics. A genetic map of 2BS, consisting of 23 SSR and one single-stranded conformation polymorphism (SSCP) marker(s), was constructed using these F2 populations. This map spanned a genetic length of 53.2 cM with average marker density of 2.3 cM. The photoperiod-sensitivity gene Ppd-B1 was mapped to chromosome arm 2BS as a SSCP molecular marker, and was validated as tightly linked to a major QTL governing late heading of CASL2BS in all mapping populations. A significant dominance by additive effect of Ppd-B1 with the LUX gene located on 3AL was also detected. CS had more copies of Ppd-B1 than CASL2BS, implying that increased copy number could elevate the expression of Ppd-1 in CS, also increasing expression of LUX and FT genes and causing CS to have an earlier heading date than CASL2BS in long days.

Extracellular ATP (eATP) has been implicated in mediating plant growth and antioxidant defense; however, it is largely unknown whether eATP might mediate salinity tolerance. We used confocal microscopy, a non-invasive vibrating ion-selective microelectrode, and quantitative real time PCR analysis to evaluate the physiological significance of eATP in the salt resistance of cell cultures derived from a salt-tolerant woody species, Populus euphratica. Application of NaCl (200 mM) shock induced a transient elevation in [eATP]. We investigated the effects of eATP by blocking P2 receptors with suramin and PPADS and applying an ATP trap system of hexokinase-glucose. We found that eATP regulated a wide range of cellular processes required for salt adaptation, including vacuolar Na⁺ compartmentation, Na⁺/H⁺ exchange across the plasma membrane (PM), K⁺ homeostasis, reactive oxygen species regulation, and salt-responsive expression of genes related to Na⁺/H⁺ homeostasis and PM repair. Furthermore, we found that the eATP signaling was mediated by H₂O₂ and cytosolic Ca²⁺ released in response to high salt in P. euphratica cells. We concluded that salt-induced eATP was sensed by purinoceptors in the PM, and this led to the induction of downstream signals, like H₂O₂ and cytosolic Ca²⁺, which are required for the up-regulation of genes linked to Na⁺/H⁺ homeostasis and PM repair. Consequently, the viability of P. euphratica cells was maintained during a prolonged period of salt stress.

Cotton (Gossypium) stem trichomes are mostly single cells that arise from stem epidermal cells. In this study, a homeodomainleucine zipper gene (HD1) was found to cosegregate with the dominant trichome locus previously designated as T1 and mapped to chromosome 6. Characterization of HD1 orthologs revealed that the absence of stem trichomes in modern Gossypium barbadense varieties is linked to a large retrotransposon insertion in the ninth exon, 2565 bp downstream from the initial codon in the At subgenome HD1 gene (At-GbHD1). In both the At and Dt subgenomes, reduced transcription of GbHD1 genes is caused by this insertion. The disruption of At-HD1 further affects the expression of downstream GbMYB25 and GbHOX3 genes. Analyses of primitive cultivated accessions identified another retrotransposon insertion event in the sixth exon of At-GbHD1 that might predate the previously identified retrotransposon in modern varieties. Although both retrotransposon insertions results in similar phenotypic changes, the timing of these two retrotransposon insertion events fits well with our current understanding of the history of cotton speciation and dispersal. Taken together, the results of genetics mapping, gene expression and association analyses suggest that GbHD1 is an important component that controls stem trichome development and is a promising candidate gene for the T1 locus. The interspecific phenotypic difference in stem trichome traits also may be attributable to HD1 inactivation associated with retrotransposon insertion. [ABSTRACT FROM AUTHOR]

Apyrase and extracellular ATP play crucial roles in mediating plant growth and defense responses. In the cold-tolerant poplar, Populus euphratica, low temperatures up-regulate APYRASE2 (PeAPY2) expression in callus cells. We investigated the biochemical characteristics of PeAPY2 and its role in cold tolerance. We found that PeAPY2 predominantly localized to the plasma membrane, but punctate signals also appeared in the endoplasmic reticulum and Golgi apparatus. PeAPY2 exhibited broad substrate specificity, but it most efficiently hydrolyzed purine nucleotides, particularly ATP. PeAPY2 preferred Mg2+ as a cofactor, and it was insensitive to various, specific ATPase inhibitors. When PeAPY2 was ectopically expressed in Arabidopsis (Arabidopsis thaliana), cold tolerance was enhanced, based on root growth measurements and survival rates. Moreover, under cold stress, PeAPY2-transgenic plants maintained plasma membrane integrity and showed reduced cold-elicited electrolyte leakage compared with wild-type plants. These responses probably resulted from efficient plasma membrane repair via vesicular trafficking. Indeed, transgenic plants showed accelerated endocytosis and exocytosis during cold stress and recovery. We found that low doses of extracellular ATP accelerated vesicular trafficking, but high extracellular ATP inhibited trafficking and reduced cell viability. Cold stress caused significant increases in root medium extracellular ATP. However, under these conditions, PeAPY2-transgenic lines showed greater control of extracellular ATP levels than wild-type plants. We conclude that Arabidopsis plants that overexpressed PeAPY2 could increase membrane repair by accelerating vesicular trafficking and hydrolyzing extracellular ATP to avoid excessive, cold-elicited ATP accumulation in the root medium and, thus, reduced ATP-induced inhibition of vesicular trafficking. [ABSTRACT FROM AUTHOR]

Virus-induced gene silencing (VIGS) has been shown to be an effective tool for investigating gene functions in herbaceous plant species, but has rarely been tested in trees. The establishment of a fast and reliable transformation system is especially important for woody plants, many of which are recalcitrant to transformation. In this study, we established a tobacco rattle virus (TRV)-based VIGS system for two Populus species, Populus euphratica and P. × canescens. Here, TRV constructs carrying a 266 bp or a 558 bp fragment of the phytoene desaturase (PDS) gene were Agrobacterium-infiltrated into leaves of the two poplar species. Agrobacterium- mediated delivery of the shorter insert, TRV2-PePDS266, into the host poplars resulted in expected photobleaching in both tree species, but not the longer insert, PePDS558. The efficiency of VIGS was temperature-dependent, increasing by raising the temperature from 18 to 28 °C. The optimized TRV-VIGS system at 28 °C resulted in a high silencing frequency and efficiency up to 65-73 and 83-94%, respectively, in the two tested poplars. Moreover, syringe inoculation of Agrobacterium in 100 mM acetosyringone induced a more efficient silencing in the two poplar species, compared with other agroinfiltration methods, e.g., direct injection, misting and agrodrench. There were plant species-related differences in the response to VIGS because the photobleaching symptoms were more severe in P. × canescens than in P. euphratica. Furthermore, VIGS-treated P. euphratica exhibited a higher recovery rate (50%) after several weeks of the virus infection, compared with TRV-infected P. × canescens plants (20%). Expression stability of reference genes was screened to assess the relative abundance of PePDS mRNA in VIGS-treated P. euphratica and P. × canescens. PeACT7 was stably expressed in P. euphratica and UBQ-L was selected as the most suitable reference gene for P. × canescens using three different statistical approaches, geNorm, NormFinder and BestKeeper. Quantitative real-time PCR showed significant reductions in PDS transcripts (55-64%) in the photobleached leaves of both VIGS-treated poplar species. Our results demonstrate that the TRV-based VIGS provides a practical tool for gene functional analysis in Populus sp., especially in those poplar species which are otherwise recalcitrant to transformation. [ABSTRACT FROM AUTHOR]

Na+ uptake and transport in Kandelia candel and antioxidative defense were investigated under rising NaCl stress from 100 to 300mM. Salinized K. candel roots had a net Na+ efflux with a declined flux rate during an extended NaCl exposure. Na+ buildup in leaves enhanced H2O2 levels, superoxide dismutase (SOD) activity, and increased transcription of CSD gene encoding a Cu/Zn SOD. Sequence and subcellular localization analyses have revealed that KcCSD is a typical Cu/Zn SOD in chloroplast. The transgenic tobacco experimental system was used as a functional genetics model to test the effect of KcCSD on salinity tolerance. KcCSD-transgenic lines were more Na+ tolerant than wild- type (WT) tobacco in terms of lipid peroxidation, root growth, and survival rate. In the latter, 100mM NaCl led to a remarkable reduction in chlorophyll content and a/b ratio, decreased maximal chlorophyll a fluorescence, and photochemical efficiency of photosystem II. NaCl stress in WT resulted from H2O2 burst in chloroplast. Na+ injury to chloroplast was less pronounced in KcCSD-transgenic plants due to upregulated antioxidant defense. KcCSD-transgenic tobacco enhanced SOD activity by an increment in SOD isoenzymes under 100mM NaCl stress from 24 h to 7 day. Catalase activity rose in KcCSD overexpressing tobacco plants. KcCSD-transgenic plants better scavenged NaCl-elicited reactive oxygen species (ROS) compared to WT ones. In conclusion, K. candel effectively excluded Na+ in roots during a short exposure; and increased CSD expression to reduce ROS in chloroplast in a long-term and high saline environment. [ABSTRACT FROM AUTHOR]

Extracellular ATP (eATP) has been implicated in mediating plant growth and antioxidant defense; however, it is largely unknown whether eATP might mediate salinity tolerance. We used confocal microscopy, a non-invasive vibrating ion-selective microelectrode, and quantitative real time PCR analysis to evaluate the physiological significance of eATP in the salt resistance of cell cultures derived from a salt-tolerant woody species, Populus euphratica. Application of NaCl (200 mM) shock induced a transient elevation in [eATP]. We investigated the effects of eATP by blocking P2 receptors with suramin and PPADS and applying an ATP trap system of hexokinase-glucose. We found that eATP regulated a wide range of cellular processes required for salt adaptation, including vacuolar Na+ compartmentation, Na+/H+ exchange across the plasma membrane (PM), K+ homeostasis, reactive oxygen species regulation, and salt-responsive expression of genes related to K+/Na+ homeostasis and PM repair. Furthermore, we found that the eATP signaling was mediated by H2O2 and cytosolic Ca2+ released in response to high salt in P. euphratica cells. We concluded that salt-induced eATP was sensed by purinoceptors in the PM, and this led to the induction of downstream signals, like H2O2 and cytosolic Ca2+, which are required for the upregulation of genes linked to K+/Na+ homeostasis and PM repair. Consequently, the viability of P. euphratica cells was maintained during a prolonged period of salt stress. [ABSTRACT FROM AUTHOR]

Background: In plants, sucrose synthase (Sus) is widely considered as a key enzyme involved in sucrose metabolism. Several paralogous genes encoding different isozymes of Sus have been identified and characterized in multiple plant genomes, while limited information of Sus genes is available to date for cotton. Results: Here, we report the molecular cloning, structural organization, phylogenetic evolution and expression profiles of seven Sus genes (GaSus1 to 7) identified from diploid fiber cotton (Gossypium arboreum). Comparisons between cDNA and genomic sequences revealed that the cotton GaSus genes were interrupted by multiple introns. Comparative screening of introns in homologous genes demonstrated that the number and position of Sus introns are highly conserved among Sus genes in cotton and other more distantly related plant species. Phylogenetic analysis showed that GaSus1, GaSus2, GaSus3, GaSus4 and GaSus5 could be clustered together into a dicot Sus group, while GaSus6 and GaSus7 were separated evenly into other two groups, with members from both dicot and monocot species. Expression profiles analyses of the seven Sus genes indicated that except GaSus2, of which the transcripts was undetectable in all tissues examined, and GaSus7, which was only expressed in stem and petal, the other five paralogues were differentially expressed in a wide ranges of tissues, and showed development-dependent expression profiles in cotton fiber cells. Conclusions: This is a comprehensive study of the Sus gene family in cotton plant. The results presented in this work provide new insights into the evolutionary conservation and sub-functional divergence of the cotton Sus gene family in response to cotton fiber growth and development. [ABSTRACT FROM AUTHOR]

Using the Affymetrix poplar genome array, we explored the leaf transcriptome of salt-tolerant Populus euphratica Oliv. and salt-sensitive P. popularis 35-44 ( P. popularis) under control and saline conditions. Our objective was to clarify the genomic differences in regulating K+/Na+ and reactive oxygen species (ROS) homeostasis between the two species. Compared to P. popularis, salt-tolerant P. euphratica responses to salinity involved induction of a relatively larger number of probesets after short-term (ST) exposure to 150 mM NaCl (24 h) and relatively fewer probesets after a long-term (LT) exposure to salinity (200 mM NaCl, 28 days). Compared to P. popularis, leaves of the control P. euphratica plants exhibited a higher transcript abundance of genes related to Na+/H+ antiport (Na+/H+ antiporters, H+ pumps) and K+ uptake and transport. Notably, the expression of these genes did not decrease (with a few exceptions) during salt treatment. Regarding ROS homeostasis, P. euphratica exhibited rapid up-regulation of a variety of antioxidant enzymes after exposure to ST salinity, indicating a rapid adaptive response to salt stress. However, the effect of NaCl on transcription in P. popularis leaves was more pronounced after exposure to prolonged salinity. LT-stressed P. popularis up-regulated some genes mediating K+/Na+ homeostasis but decreased transcription of main scavengers of superoxide radicals and H2O2 except for some isoforms of a few scavengers. Mineral and ROS analyses show that NaCl induced a marked increase of leaf Na+ and H2O2 in LT-stressed plants of the two species and the effects were even more pronounced in the salt-sensitive poplar. We place the transcription results in the context of our physiological measurements to infer some implications of NaCl-induced alterations in gene expression related to K+/Na+ and ROS homeostasis. [ABSTRACT FROM AUTHOR]