Genome-wide identification, characterization, and expression analysis of the small auxin-up RNA gene family during zygotic and somatic embryo maturation of the cacao tree (Theobroma cacao).

Small auxin-up RNA (SAUR) proteins were known as a large family that supposedly participated in various biological processes in higher plant species. However, the SAUR family has been still not explored in cacao (Theobroma cacao L.), one of the most important industrial trees. The present work, as an in silico study, revealed comprehensive aspects of the structure, phylogeny, and expression of TcSAUR gene family in cacao. A total of 90 members of the TcSAUR gene family have been identified and annotated in the cacao genome. According to the physic-chemical features analysis, all TcSAUR proteins exhibited slightly similar characteristics. Phylogenetic analysis showed that these TcSAUR proteins could be categorized into seven distinct groups, with 10 sub-groups. Our results suggested that tandemly duplication events, segmental duplication events, and whole genome duplication events might be important in the growth of the TcSAUR gene family in cacao. By re-analyzing the available transcriptome databases, we found that a number of TcSAUR genes were exclusively expressed during the zygotic embryogenesis and somatic embryogenesis. Taken together, our study will be valuable to further functional characterizations of candidate TcSAUR genes for the genetic engineering of cacao.

Insights into the gene and protein structures of the CaSWEET family members in chickpea (Cicer arietinum), and their gene expression patterns in different organs under various stress and abscisic acid treatments.

'Sugars Will Eventually be Exported Transporters' (SWEETs) are a group of sugar transporters that play crucial roles in various biological processes, particularly plant stress responses. However, no information is available yet for the CaSWEET family in chickpea. Here, we identified all putative CaSWEET members in chickpea, and obtained their major characteristics, including physicochemical patterns, chromosomal distribution, subcellular localization, gene organization, conserved motifs and three-dimensional protein structures. Subsequently, we explored available transcriptome data to compare spatiotemporal transcript abundance of CaSWEET genes in various major organs. Finally, we studied the changes in their transcript levels in leaves and/or roots following dehydration and exogenous abscisic acid treatments using RT-qPCR to obtain valuable information underlying their potential roles in chickpea responses to water-stress conditions. Our results provide the first insights into the characteristics of the CaSWEET family members and a foundation for further functional characterizations of selected candidate genes for genetic engineering of chickpea.

Genome-Wide Association Mapping of Salinity Tolerance at the Seedling Stage in a Panel of Vietnamese Landraces Reveals New Valuable QTLs for Salinity Stress Tolerance Breeding in Rice.

Rice tolerance to salinity stress involves diverse and complementary mechanisms, such as the regulation of genome expression, activation of specific ion-transport systems to manage excess sodium at the cell or plant level, and anatomical changes that avoid sodium penetration into the inner tissues of the plant. These complementary mechanisms can act synergistically to improve salinity tolerance in the plant, which is then interesting in breeding programs to pyramidize complementary QTLs (quantitative trait loci), to improve salinity stress tolerance of the plant at different developmental stages and in different environments. This approach presupposes the identification of salinity tolerance QTLs associated with different mechanisms involved in salinity tolerance, which requires the greatest possible genetic diversity to be explored. To contribute to this goal, we screened an original panel of 179 Vietnamese rice landraces genotyped with 21,623 SNP markers for salinity stress tolerance under 100 mM NaCl treatment, at the seedling stage, with the aim of identifying new QTLs involved in the salinity stress tolerance via a genome-wide association study (GWAS). Nine salinity tolerance-related traits, including the salt injury score, chlorophyll and water content, and K+ and Na+ contents were measured in leaves. GWAS analysis allowed the identification of 26 QTLs. Interestingly, ten of them were associated with several different traits, which indicates that these QTLs act pleiotropically to control the different levels of plant responses to salinity stress. Twenty-one identified QTLs colocalized with known QTLs. Several genes within these QTLs have functions related to salinity stress tolerance and are mainly involved in gene regulation, signal transduction or hormone signaling. Our study provides promising QTLs for breeding programs to enhance salinity tolerance and identifies candidate genes that should be further functionally studied to better understand salinity tolerance mechanisms in rice.