GbCYP86A1‐1 from Gossypium barbadense positively regulates defence against Verticillium dahliae by cell wall modification and activation of immune pathways

Abstract

SummarySuberin acts as stress‐induced antipathogen barrier in the root cell wall. CYP86A1 encodes cytochrome P450 fatty acid ω‐hydroxylase, which has been reported to be a key enzyme for suberin biosynthesis; however, its role in resistance to fungi and the mechanisms related to immune responses remain unknown. Here, we identified a disease resistance‐related gene, GbCYP86A1‐1, from Gossypium barbadense cv. Hai7124. There were three homologs of GbCYP86A1 in cotton, which are specifically expressed in roots and induced by Verticillium dahliae. Among them, GbCYP86A1‐1 contributed the most significantly to resistance. Silencing of GbCYP86A1‐1 in Hai7124 resulted in severely compromised resistance to V. dahliae, while heterologous overexpression of GbCYP86A1‐1 in Arabidopsis improved tolerance. Tissue sections showed that the roots of GbCYP86A1‐1 transgenic Arabidopsis had more suberin accumulation and significantly higher C16‐C18 fatty acid content than control. Transcriptome analysis revealed that overexpression of GbCYP86A1‐1 not only affected lipid biosynthesis in roots, but also activated the disease‐resistant immune pathway; genes encoding the receptor‐like kinases (RLKs), receptor‐like proteins (RLPs), hormone‐related transcription factors, and pathogenesis‐related protein genes (PRs) were more highly expressed in the GbCYP86A1‐1 transgenic line than control. Furthermore, we found that when comparing V. dahliae ‐inoculated and noninoculated plants, few differential genes related to disease immunity were detected in the GbCYP86A1‐1 transgenic line; however, a large number of resistance genes were activated in the control. This study highlights the role of GbCYP86A1‐1 in the defence against fungi and its underlying molecular immune mechanisms in this process.

Root Physiological Traits and Transcriptome Analyses Reveal that Root Zone Water Retention Confers Drought Tolerance to Opisthopappus taihangensis

“…In this study, the histochemical observations showed that O. taihangensis roots underwent strong suberin depositions in both endodermal and exodermal cell walls in response to drought stress (Fig. 2), which was also observed in grapevine, barley and Gossypium barbadense [64][65][66] . Correspondingly, genes encoding cytochrome P450 enzymes (CYP86A1), fatty acyl reductase (FAR4), and long-chain acyl-CoA synthetase (LACS1) involved in the suberin biosynthesis pathway were upregulated in the drought-stressed roots of O. taihangensis (Fig.…”

“…In Arabidopsis, CYP86A1 and FAR4, which are expressed in the roots, have been identified as key genes for root suberin biosynthesis 67,68 . For example, the overexpression of GbCYP86A1-1 in Arabidopsis enabled transgenic lines to accumulate more suberin in the roots than the control 66 . In addition, in the FAR4 loss-of-function mutants, individual chain lengths of primary alcohols of root suberin were significantly reduced 68 .…”

Proteomic and Transcriptomic Analyses Indicate Metabolic Changes and Reduced Defense Responses in Mycorrhizal Roots of Oeceoclades maculata (Orchidaceae) Collected in Nature

“…Plant defense responses to colonization by pathogenic fungi usually involve the induction of enzymes that can degrade the fungal cell wall, as well as pathogenesis-related (PR) proteins and proteins involved in plant cell wall modification [ 57 , 58 ]. Although two PR proteins were found by proteomics to be more expressed in mycorrhizal roots of O. maculata , transcriptomic data indicated that plant defense responses were lower in mycorrhizal roots than in non-mycorrhizal roots.…”

Peer Review #2 of "Transcriptome sequencing of Verticillium dahliae from a cotton farm reveals positive correlation between virulence and tolerance of sugar-induced hyperosmosis (v0.1)"

“…The mechanisms in response to pathogen attack are divided into two groups, pre-existing and induced. The pre-existing mechanisms mainly involve physical and chemical barriers for protecting plants from pathogen infestation at the first line, including the plant cuticle, cell wall, and antimicrobial compounds (Pieterse et al, 2009;Wang et al, 2019). Salicylic acid (SA) crosstalking with auxin, ethylene, and jasmonates (JA) is crucial for the inducible response of plants to pathogens infection including systemic acquired resistance and induced systemic resistance (Pieterse et al, 1998;Lopez et al, 2008;Vlot et al, 2009).…”