Cotton is widely grown in many countries around the world due to the huge economic value of the total natural fiber. Verticillium wilt, caused by the soil-borne pathogen Verticillium dahliae, is the most devastating disease that led to extensive yield losses and fiber quality reduction in cotton crops. Developing resistant cotton varieties through genetic engineering is an effective, economical, and durable strategy to control Verticillium wilt. However, there are few resistance gene resources in the currently planted cotton varieties, which has brought great challenges and difficulties for breeding through genetic engineering. Further revealing the molecular mechanism between V. dahliae and cotton interaction is crucial to discovering genes related to disease resistance. In this review, we elaborated on the pathogenic mechanism of V. dahliae and the resistance mechanism of cotton to Verticillium wilt. V. dahliae has evolved complex mechanisms to achieve pathogenicity in cotton, mainly including five aspects: (1) germination and growth of microsclerotia; (2) infection and successful colonization; (3) adaptation to the nutrient-deficient environment and competition of nutrients; (4) suppression and manipulation of cotton immune responses; (5) rapid reproduction and secretion of toxins. Cotton has evolved multiple physiological and biochemical responses to cope with V. dahliae infection, including modification of tissue structures, accumulation of antifungal substances, homeostasis of reactive oxygen species (ROS), induction of Ca²⁺ signaling, the mitogen-activated protein kinase (MAPK) cascades, hormone signaling, and PAMPs/effectors-triggered immune response (PTI/ETI). This review will provide an important reference for the breeding of new cotton germplasm resistant to Verticillium wilt through genetic engineering.

Patatin-like proteins (PLPs) have non-specific lipid acyl hydrolysis (LAH) activity, which can hydrolyze membrane lipids into fatty acids and lysophospholipids. The vital role of PLPs in plant growth and abiotic stress has been well documented. However, the function of PLPs in plant defense responses against pathogens is still poorly understood. Here, we isolated and identified a novel cotton (Gossypium hirsutum) PLP gene GhPLP2. The expression of GhPLP2 was induced upon treatment with Verticillium dahliae, the signaling molecules jasmonic acid (JA) and ethylene (ETH) in cotton plants. Subcellular localization revealed that GhPLP2 was localized to the plasma membrane. GhPLP2-silenced cotton plants were more susceptible to infection by V. dahliae, while the overexpression of GhPLP2 in Arabidopsis enhanced its resistance to V. dahliae, which was apparent as mild symptoms, and a decrease in the disease index and fungal biomass. The hypersensitive response, deposition of callose, and H₂O₂ accumulation triggered by V. dahliae elicitor were reduced in GhPLP2-silenced cotton plants. The overexpression of GhPLP2 in Arabidopsis resulted in the accumulation of linoleic acid (LA, 18:2) and α-linolenic acid (ALA, 18:3) and facilitated the biosynthesis of JA and JA-mediated defensive responses. GhPLP2 silencing in cotton plants consistently reduced the accumulation of linoleic acid (LA, 18:2) and α-linolenic acid (ALA, 18:3) and suppressed the biosynthesis of JA and the defensive responses mediated by JA. These results indicate that GhPLP2 is involved in the resistance of cotton to V. dahliae by maintaining fatty acid metabolism pools for JA biosynthesis and activating the JA signaling pathway.

Background: Basic leucine zipper (bZIP) protein is a plant-specific transcription factor involved in various biological processes, including light signaling, seed maturation, flower development, cell elongation, seed accumulation protein, and abiotic and biological stress responses. However, little is known about the pea bZIP family. Results: In this study, we identified 87 bZIP genes in pea, named PsbZIP1 ~ PsbZIP87, via homology analysis using Arabidopsis. The genes were divided into 12 subfamilies and distributed unevenly in 7 pea chromosomes. PsbZIPs in the same subfamily contained similar intron/exon organization and motif composition. 1 tandem repeat event and 12 segmental duplication events regulated the expansion of the PsbZIP gene family. To better understand the evolution of the PsbZIP gene family, we conducted collinearity analysis using Arabidopsis thaliana, Oryza sativa Japonica, Fagopyrum tataricum, Solanum lycopersicum, Vitis vinifera, and Brachypodium distachyon as the related species of pea. In addition, interactions between PsbZIP proteins and promoters containing hormone- and stress-responsive cis-acting elements suggest that the regulation of PsbZIP expression was complex. We also evaluated the expression patterns of bZIP genes in different tissues and at different fruit development stages, all while subjecting them to five hormonal treatments. Conclusion: These results provide a deeper understanding of PsbZIP gene family evolution and resources for the molecular breeding of pea. The findings suggested that PsbZIP genes, specifically PSbZIP49, play key roles in the development of peas and their response to various hormones.

Background/Objectives: Licorice (Glycyrrhiza glabra L.) is a highly important medicinal plant that is widely used in China owing to its active ingredients. Its main active components are flavonoids, including liquiritigenin, liquiritin and licochalcone A. The hairy roots (HRs) induced by Agrobacterium rhizogenes are a commonly used chassis in synthetic biology to enhance the production of active compounds in medicinal plants. Methods: A biosynthesis system to acquire the active ingredients of G. glabra was established using an HR culture system. It employed a transcriptome analysis to identify the change in gene expression following treatment with methyl jasmonate (MeJA). Results: After 28 days of suspension culture, the biomass of HRs increased by approximately 34.5-fold and reached 1.83 g/100 mL flask. Treatment with MeJA significantly increased the contents of liquiritigenin, liquiritin, and glabridin in the HRs. The transcriptome data indicated that MeJA activated the flavonoid biosynthetic pathway genes in the HRs, which was largely consistent with the qRT-PCR results. Furthermore, the overexpression of the GgCHS6 gene substantially increased the content of flavonoids in HRs. Conclusions: Collectively, this study established an HR system to biosynthesize the active ingredients of G. glabra using metabolic engineering and genetic engineering techniques and provides several valuable candidate genes for further functional study.