lncRNA7 and lncRNA2 modulate cell wall defense genes to regulate cotton resistance to Verticillium wilt

Abstract

In plants, long non-coding RNAs regulate disease resistance against fungi and other pathogens. However, the specific mechanism behind this regulation remains unclear. In this study, we identified disease resistance-related lncRNAs as well as their regulating genes and assessed their functions by infection of cotton (Gossypium) chromosome segment substitution lines with Verticillium dahliae. Our results demonstrated that lncRNA7 and its regulating gene Pectin methylesterase inhibitor 13 (GbPMEI13) positively regulated disease resistance via the silencing approach, while ectopic overexpression of GbPMEI13 in Arabidopsis (Arabidopsis thaliana) promoted growth and enhanced resistance to V. dahliae. In contrast, lncRNA2 and its regulating gene Polygalacturonase 12 (GbPG12) negatively regulated resistance to V. dahliae. We further found that fungal disease-related agents, including the pectin-derived oligogalacturonide (OG), could down-regulate the expression of lncRNA2 and GbPG12, leading to pectin accumulation. Conversely, OG up-regulated the expression of lncRNA7, which encodes a plant peptide phytosulfokine (PSK-α), which was confirmed by lncRNA7 overexpression and UPLC-MS experiments. We showed that PSK-α promoted IAA accumulation and activated GbPMEI13 expression through Auxin Response Factor 5 (ARF5). Since it is an inhibitor of pectin methylesterase (PME), GbPMEI13 promotes pectin methylation and therefore increases the resistance to V. dahliae. Consistently, we also demonstrated that GbPMEI13 inhibits the mycelial growth and spore germination of V. dahliae in vitro. In this study, we demonstrated that lncRNA7, lncRNA2, and their regulating genes modulate cell wall defense against V. dahliae via auxin-mediated signaling, providing a strategy for cotton breeding.

The Conservation of Long Intergenic Non-Coding RNAs and Their Response to Verticillium dahliae Infection in Cotton

“…Despite the inconsistency, we also found more Vd -responsive QTL in D t than in A t for the stringently selected Vd -responsive lincRNAs. For the two lncRNAs ( lncRNA2 and lncRNA7 ) that have been demonstrated to be regulators of Vd resistance [ 33 ], although lncRNA7 was not identified in this study, lncRNA2 was identified, despite its expression change upon Vd infection being insignificant. These results suggest that the repertoire of Vd -responsive lncRNAs is not yet saturated and that the same lncRNA might respond differently to Vd infection due to different genetic background and/or different Vd isolates.…”

“…While it is still under debate whether the transcribed lincRNAs are functionally relevant, many lincRNAs have been demonstrated to be important regulators of diverse biological processes [ 44 , 45 ], including some preliminary results achieved in cotton [ 25 , 27 , 30 , 32 , 33 ]. Nevertheless, owing to the huge number of lincRNAs identified and their unique characteristics, such as low and tissue-specific expression, it is still a challenge to know which of them are functionally important, so they should be chosen for in-depth functional investigation to understand their underlying regulatory mechanism(s).…”

“…A few studies have investigated Vd -responsive cotton lncRNAs [ 24 , 26 , 33 ]. One of those studies found more Vd -responsive lncRNAs in the D t subgenome than in the A t subgenome in both Ghr and Gba, and, consistently, slightly more Vd -responsive QTL were found in D t than in A t [ 26 ].…”

“…The study also found that lncRNAs could be heavily involved in Vd response by regulating the JA pathway and demonstrated that the expression level of both GhlncLOX3 and its trans-target GhLOX3 is positively correlated with the Vd -resistance level of Ghr cultivars and that down-regulating GhlncLOX3 in resistant Ghr cultivar by VIGS compromises the Vd resistance of the Ghr cultivar [ 24 ]. In addition, lncRNA2 and lncRNA7 were found to be negative and positive regulator of Vd resistance, respectively, by modulating genes involved in cell-wall development [ 33 ].…”

Advanced genes expression pattern greatly contributes to divergence in Verticillium wilt resistance between Gossypium barbadense and Gossupium hirsutum

“…Long non-coding RNA lncRNA7 and its regulating gene Pectin methylesterase inhibitor 13 ( GbPMEI13 ) positively regulate disease resistance via a silencing approach. In contrast, lncRNA2 and its regulating gene Polygalacturonase 12 ( GbPG12 ) negatively regulated resistance to V. dahliae ( Zhang L. et al, 2022 ). By identifying 41 conserved ENODLs in G. hirsutum , Zhang M. et al (2022) found GhENODL6 was upregulated under V. dahliae stress and hormonal signal and displayed higher transcript levels in resistant cotton than the susceptible.…”