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Mini zinc fingers constitute a class of microproteins that appeared early in evolution and expanded in seeds plants. In this review, the phylogenetic history, the functions and the mode of action of Mini zinc fingers in plants are reported and discussed. It appears that mini zinc fingers play an important role in the control of plant development. They are involved in the control of cell division and expansion, in the switch between the determinate/indeterminate state of the meristems and in the regulation of vegetative growth and floral organ development. Their biochemical mode of action seems to be diverse. In some studies, it has been reported that mini zinc fingers can directly bind to DNA and activate target gene expression, whereas other studies have shown that they can interact with and inhibit the activity of specific zinc finger homeodomain transcription factors or act as adaptor proteins necessary to aggregate polymeric protein complexes corresponding to chromatin remodelling factors negatively regulating the expression of specific genes. The diversity of mode of action for mini zinc finger microproteins suggests a wider range of biological functions than what has been that described in the literature thus far, and their involvement in the response to biotic and abiotic stresses should be further investigated in future studies. • Mini zinc fingers are a class of microproteins particularly prevalent in seed plants. • Mini zinc fingers perform their function via protein‒protein and/or protein‒DNA interactions. • Mini zinc fingers are major regulators of vegetative and reproductive plant development. • Mini zinc finger function in the plant response to stresses should be further explored. [ABSTRACT FROM AUTHOR]

Leaf traits are often strongly correlated with yield, which poses a major challenge in rice breeding. In the present study, using a panel of Vietnamese rice landraces genotyped with 21,623 single-nucleotide polymorphism markers, a genome-wide association study (GWAS) was conducted for several leaf traits during the vegetative stage. Vietnamese landraces are often poorly represented in panels used for GWAS, even though they are adapted to contrasting agrosystems and can contain original, valuable genetic determinants. A panel of 180 rice varieties was grown in pots for four weeks with three replicates under nethouse conditions. Different leaf traits were measured on the second fully expanded leaf of the main tiller, which often plays a major role in determining the photosynthetic capacity of the plant. The leaf fresh weight, turgid weight and dry weight were measured; then, from these measurements, the relative tissue weight and leaf dry matter percentage were computed. The leaf dry matter percentage can be considered a proxy for the photosynthetic efficiency per unit leaf area, which contributes to yield. By a GWAS, thirteen QTLs associated with these leaf traits were identified. Eleven QTLs were identified for fresh weight, eleven for turgid weight, one for dry weight, one for relative tissue weight and one for leaf dry matter percentage. Eleven QTLs presented associations with several traits, suggesting that these traits share common genetic determinants, while one QTL was specific to leaf dry matter percentage and one QTL was specific to relative tissue weight. Interestingly, some of these QTLs colocalize with leaf- or yield-related QTLs previously identified using other material. Several genes within these QTLs with a known function in leaf development or physiology are reviewed. [ABSTRACT FROM AUTHOR]

Functional analyses of MADS-box transcription factors in plants have unraveled their role in major developmental programs (e.g. flowering and floral organ identity) as well as stress-related developmental processes, such as abscission, fruit ripening, and senescence. Overexpression of the rice (Oryza sativa) MADS26 gene in rice has revealed a possible function related to stress response. Here, we show that OsMADS26-down-regulated plants exhibit enhanced resistance against two major rice pathogens: Magnaporthe oryzae and Xanthomonas oryzae. Despite this enhanced resistance to biotic stresses, OsMADS26-down-regulated plants also displayed enhanced tolerance to water deficit. These phenotypes were observed in both controlled and field conditions. Interestingly, alteration of OsMADS26 expression does not have a strong impact on plant development. Gene expression profiling revealed that a majority of genes misregulated in overexpresser and down-regulated OsMADS26 lines compared with control plants are associated to biotic or abiotic stress response. Altogether, our data indicate that OsMADS26 acts as an upstream regulator of stress-associated genes and thereby, a hub to modulate the response to various stresses in the rice plant. [ABSTRACT FROM AUTHOR]

Plants adjust their development in relation to the availability of nutrient sources. This necessitates signaling between root and shoot. Aside from the well-known systemic signaling processes mediated by auxin, cytokinin, and sugars, new pathways involving carotenoid-derived hormones have recently been identified. The auxin-responsive MAX pathway controls shoot branching through the biosynthesis of strigolactone in the roots. The BYPASS1 gene affects the production of an as-yet unknown carotenoid-derived substance in roots that promotes shoot development. Novel local and systemic mechanisms that control adaptive root development in response to nitrogen and phosphorus starvation were recently discovered. Notably, the ability of the NITRATE TRANSPORTER 1.1 to transport auxin drew for the first time a functional link between auxin, root development, and nitrate availability in soil. The study of plant response to phosphorus starvation allowed the identification of a systemic mobile miRNA. Deciphering and integrating these signaling pathways at the whole-plant level provide a new perspective for understanding how plants regulate their development in response to environmental cues. [ABSTRACT FROM AUTHOR]

A novel cDNA (Crubie2) encoding ubiquitin‐conjugating enzyme E2 was isolated from a Catharanthus roseus cDNA library. Sequence comparison with Arabidopsis thaliana E2 sequences revealed that CrUBIE2 is a member of a new plant E2 sub‐family. Expression of Crubie2 is repressed in developing organs and down‐regulated by cytokinin suggesting that a decrease in the ubiquitin‐dependent proteolytic pathway may take part in the regulation of alkaloid biosynthesis in C. roseus cell suspensions. [ABSTRACT FROM AUTHOR]

Abstract: In plants, MADS-box transcription factors are key regulators of floral and fruit development, organ dehiscence and stress responses. Nevertheless, the functions of most of them are still unknown. In Arabidopsis thaliana, the AGL17-like clade of MADS-box transcription factors comprises four members. AGL17 is involved in floral induction, whereas AGL44/ANR1 is involved in the adaptive development of roots in response to nitrate. AGL21 is primarily expressed in the roots and AGL16 in the leaves, suggesting that these transcription factors may be involved in the control of vegetative development. In Oryza sativa, the AGL17-like clade comprises five members, OsMADS23, OsMADS25, OsMADS27, OsMADS57 and OsMADS61. In a first attempt to characterize their functions, we used promoter::Gus reporter gene fusions and RT-qPCR to study the expression patterns of these genes and their regulation by different external stimuli. The OsMADS23, OsMADS25, OsMADS27 and OsMADS57 promoters were active in the root’s central cylinder. In addition, the OsMADS57 promoter was active in leaves, whereas the OsMADS61 promoter was only active in the leaf tips and the stem base. OsMADS25 and OsMADS27 transcripts accumulated in response to osmotic stress, whereas the expression levels of OsMADS25, OsMADS27 and OsMADS57 were slightly induced by nitrate. Each of these five genes was responsive to various hormonal treatments. These distinct expression patterns indicate that these five genes have specific and non-redundant functions that likely differs from those of their A. thaliana homologs. [Copyright &y& Elsevier]