Identification of photoperiod-regulated gene in soybean and functional analysis in Nicotiana benthamiana

Integrated physiological, transcriptomic and metabolomic analyses reveal potential mechanisms of potato tuber dormancy release

Regulating potato tuber dormancy is crucial for crop productivity and food security. We conducted the first comprehensive physiological, transcriptomic, and metabolomic investigations of two varieties of long and short dormant potato tubers in order to clarify the mechanisms of dormancy release. In the current study, three different dormant stages of UGT (ungerminated tubers), MGT (minimally germinated tubers), and GT (germinated tubers) were obtained by treatment with the germination promoter gibberellin A3 and the germination inhibitor chlorpropham. The results revealed that the contents of reducing reducing sugar, sucrase, glutamine synthetase, and nitrate reductase were increased in the dormancy release stages, whereas the contents of sucrose and starch were decreased, leading to a change in the phenotype of the potato tuber bud eyes. According to transcriptomic and metabolomic investigations, four metabolomic pathways were impacted by the dormancy release process. Zeatin biosynthesis was identified in both potato varieties in the dormant release stage (trans-zeatin riboside, isopentenyl adenosine, 5'-methylthioadenosine, IPT, CYP735A, CKX, and UGT73C); glutathione metabolism was identified in short-dormant potato varieties ((5-L-Glutamyl)-L-amino acid, oxidized glutathione, GPX, IDH1, GGT1_5, and GST); and the pentose phosphate pathway (D-Xylulose 5-phosphate, ribose 1-phosphate, PGD, and RPIA) and the phenylpropanoid biosynthesis (caffeic acid, sinapine, CYP98A, and CSE) were identified in long-dormant potato varieties. In conclusion, the four pathways mentioned above involve DEGs and DEMs that are crucial to the control of tuber dormancy release. This work offers a theoretical foundation and useful recommendations for potato tuber quality improvement and molecular breeding.

Identification of candidate flowering and sex genes in white Guinea yam (D. rotundata Poir.) by SuperSAGE transcriptome profiling

Dioecy (distinct male and female individuals) and scarce to non-flowering are common features of cultivated yam (Dioscorea spp.). However, the molecular mechanisms underlying flowering and sex determination in Dioscorea are largely unknown. We conducted SuperSAGE transcriptome profiling of male, female and monoecious individuals to identify flowering and sex-related genes in white Guinea yam (D. rotundata), generating 20,236 unique tags. Of these, 13,901 were represented by a minimum of 10 tags. A total 88 tags were significantly differentially expressed in male, female and monoecious plants, of which 18 corresponded to genes previously implicated in flower development and sex determination in multiple plant species. We validated the SuperSAGE data with quantitative real-time PCR (qRT-PCR)-based analysis of the expression of three candidate genes.

We further investigated the flowering patterns of 1938 D. rotundata accessions representing diverse geographical origins over two consecutive years. Over 85% of accessions were either male or non-flowering, less than 15% were female, while monoecious plants were rare. Intensity of flowering varied between male and female plants, with the former flowering more abundantly than the latter. Candidate genes identified in this study can be targeted for further validation and to induce regular flowering in poor to non-flowering cultivars. Findings of the study provide important inputs for further studies aiming to overcome the challenge of flowering in yams and to improve efficiency of yam breeding.

Molecular approaches for genetic improvement of seed quality and characterization of genetic diversity in soybean: a critical review

Soybean is an economically important leguminous crop. Genetic improvements of soybeans have focused on enhancement of seed and oil yield, development of varieties suited to different cropping systems, and breeding resistant/tolerant varieties for various biotic and abiotic stresses. Plant breeders have used conventional breeding techniques for the improvement of these traits in soybean. The conventional breeding process can be greatly accelerated through the application of molecular and genomic approaches. Molecular markers have proved to be a new tool in soybean breeding by enhancing selection efficiency in a rapid and time-bound manner. An overview of molecular approaches for the genetic improvement of soybean seed quality parameters, considering recent applications of marker-assisted selection and 'omics' research, is provided in this article.