Verticillium wilt, primarily induced by the soil-borne fungus Verticillium dahliae, is a serious threat to cotton fiber production. There are a large number of really interesting new gene (RING) domain-containing E3 ubiquitin ligases in Arabidopsis, of which three (At2g39720 (AtRHC2A), At3g46620 (AtRDUF1), and At5g59550 (AtRDUF2)) have a domain of unknown function (DUF) 1117 domain in their C-terminal regions. This study aimed to detect and characterize the RDUF members in cotton, to gain an insight into their roles in cotton’s adaptation to environmental stressors. In this study, a total of 6, 7, 14, and 14 RDUF (RING-DUF1117) genes were detected in Gossypium arboretum, G. raimondii, G. hirsutum, and G. barbadense, respectively. These RDUF genes were classified into three groups. The genes in each group were highly conserved based on gene structure and domain analysis. Gene duplication analysis revealed that segmental duplication occurred during cotton evolution. Expression analysis revealed that the GhRDUF genes were widely expressed during cotton growth and under abiotic stresses. Many cis-elements related to hormone response and environment stressors were identified in GhRDUF promoters. The predicted target miRNAs and transcription factors implied that GhRDUFs might be regulated by gra-miR482c, as well as by transcription factors, including MYB, C2H2, and Dof. The GhRDUF genes responded to cold, drought, and salt stress and were sensitive to jasmonic acid, salicylic acid, and ethylene signals. Meanwhile, GhRDUF4D expression levels were enhanced after V. dahliae infection. Subsequently, GhRDUF4D was verified by overexpression in Arabidopsis and virus-induced gene silencing treatment in upland cotton. We observed that V. dahliae resistance was significantly enhanced in transgenic Arabidopsis, and weakened in GhRDUF4D silenced plants. This study conducted a comprehensive analysis of the RDUF genes in Gossypium, hereby providing basic information for further functional studies.

Cottonseed oil is rich in unsaturated fatty acids (UFAs) and serves as an edible oil in human nutrition. Reports suggest that acyl-coenzyme A: diacylglycerol acyltransferases (DGAT) and wax ester synthase/DGAT (WSD1) genes encode a key group of enzymes that catalyze the final step for triacylglycerol biosynthesis and enable an important rate-limiting process. However, their roles in oil biosynthesis and the fatty acid profile of cotton seed are poorly understood. Therefore, the aim of this study was to identify and characterize DGAT and WSD1 genes in cotton plants and examine their roles in oil biosynthesis, the fatty acid profile of cotton seeds, and abiotic stress responses. In this study, 36 GhDGAT and GhWSD1 genes were identified in upland cotton (G. hirsutum) and found to be clustered into four groups: GhDGAT1, GhDGAT2, GhDGAT3, and GhWSD1. Gene structure and domain analyses showed that the GhDGAT and GhWSD1 genes in each group are highly conserved. Gene synteny analysis indicated that segmental and tandem duplication events occurred frequently during cotton evolution. Expression analysis revealed that GhDGAT and GhWSD1 genes function widely in cotton development and stress responses; moreover, several environmental stress and hormone response-related cis-elements were detected in the GhDGAT and GhWSD1 promoter regions. The predicted target transcription factors and miRNAs imply an extensive role of GhDGAT and GhWSD1 genes in stress responses. Increases in GhDGAT3 gene expression with increases in cottonseed oil accumulation were observed. Transformation study results showed that there was an increase in C18:1 content and a decrease in C18:2 and C18:3 contents in seeds of Arabidopsis transgenic plants overexpressing GhDGAT3D compared with that of control plants. Overall, these findings contributed to the understanding of the functions of GhDGAT and GhWSD1 genes in upland cotton, providing basic information for further research.

Verticillium wilt in cotton (Gossypium hirsutum) is primarily caused by Verticillium dahliae. Previous data suggest that prenylated RAB acceptors (PRAs) play essential roles in environmental plant adaptation, although the potential roles of PRA1 in cotton are unclear. Therefore, in this study, PRA1 family members were identified in G. hirsutum, and their roles in biotic and abiotic stresses were analyzed. Thirty-seven GhPRA1 family members were identified in upland cotton, which were divided into eight groups. Gene structure and domain analyses revealed that the sequences of GhPRA1 members in each group were highly conserved. Many environmental stress-related and hormone-response cis-acting elements were identified in the GhPRA1 promoter regions, indicating that they may respond to biotic and abiotic stresses. Expression analysis revealed that GhPRA1 members were widely expressed in upland cotton. The GhPRA1 genes responded to abiotic stress: drought, cold, salt, and heat stress. GhPRA1.B1-1A expression increased after V. dahliae infection. Furthermore, the functional role of GhPRA1.B1-1A was confirmed by overexpression in Arabidopsis thaliana, which enhanced the resistance to V. dahliae. In contrast, V. dahliae resistance was significantly weakened via virus-induced gene silencing of GhPRA1.B1-1A in upland cotton. Simultaneously, reactive oxygen species accumulation; the H₂O₂, salicylic acid, and jasmonic acid contents; and callose deposition were significantly decreased in cotton plants with GhPRA1.B1-1A silencing. These findings contribute to a better understanding of the biological roles of GhPRA1 proteins and provide candidate genes for cotton breeders for breeding V. dahliae-resistant cultivars.

Background: Cyperus esculentus L. is a unique tuber oil crop, in which tuber size directly determines both yield and oil storage capacity. It is crucial to clarify the tuber expansion pattern and explore the key genes associated with tuber expansion in Cyperus esculentus for crop improvement. Methods: This study conducted comprehensive morphological and cytological observations as well as transcriptomic analysis of tubers at multiple developmental stages. Tubers at 1, 5, 10, and 15 d were collected for transcriptome sequencing to identify differentially expressed genes (DEGs) and differentially expressed transcription factors. Gene ontology (GO) enrichment analysis was used to determine key functional categories. RT-qPCR was employed to verify the expression patterns of key genes. Results: Cyperus esculentus tubers expanded rapidly from 1 d to 15 d after initial tuber formation, and the expansion rate exhibited a trend of increasing first (1~5 d) and then decreasing (5~15 d). Cell expansion, rather than number, mainly contributed to tuber expansion. By combining the analysis of differential expression and the variation pattern of tuber expansion rate, 822 DEGs were identified to be associated with tuber expansion. GO enrichment analysis revealed that 20 genes were significantly enriched in GO:0043231 (cell wall), especially five remarkable genes encoding expansin, which exercise the function of cell wall loosening and have been proven to be associated with cell expansion. In addition, 57 differentially expressed TFs were further identified to be associated with tuber expansion. Conclusions: This study revealed the tuber expansion pattern of Cyperus esculentus and identified several key genes and TFs, which will facilitate the construction of the regulatory network and the analysis of the mechanism of tuber expansion in Cyperus esculentus.