GhTBL34 Is Associated with Verticillium Wilt Resistance in Cotton.

Jianhua Lu,Huijuan Jing,Pei Zhao,Hongmei Wang,Xiaohui Sang,Wei Chen,Xuelin Li,Yunlei Zhao

doi:10.3390/ijms22179115

Abstract

Verticillium wilt (VW) is a typical fungal disease affecting the yield and quality of cotton. The Trichome Birefringence-Like protein (TBL) is an acetyltransferase involved in the acetylation process of cell wall polysaccharides. Up to now, there are no reports on whether the TBL gene is related to disease resistance in cotton. In this study, we cloned a cotton TBL34 gene located in the confidence interval of a major VW resistance quantitative trait loci and demonstrated its relationship with VW resistance in cotton. Analyzing the sequence variations in resistant and susceptible accessions detected two elite alleles GhTBL34-2 and GhTBL34-3, mainly presented in resistant cotton lines whose disease index was significantly lower than that of susceptible lines carrying the allele GhTBL34-1. Comparing the TBL34 protein sequences showed that two amino acid differences in the TBL (PMR5N) domain changed the susceptible allele GhTBL34-1 into the resistant allele GhTBL34-2 (GhTBL34-3). Expression analysis showed that the TBL34 was obviously up-regulated by infection of Verticillium dahliae and exogenous treatment of ethylene (ET), and salicylic acid (SA) and jasmonate (JA) in cotton. VIGS experiments demonstrated that silencing of TBL34 reduced VW resistance in cotton. We deduced that the TBL34 gene mediating acetylation of cell wall polysaccharides might be involved in the regulation of resistance to VW in cotton.

Highlights

Cotton (Gossypium spp.) is an important economic crop in the world and provides the most important natural fiber for the textile industry
T test showed that disease index of resistant lines carrying the alleles GhTBL34-2 and GhTBL34-3 was significantly lower than that of susceptible lines carrying the allele GhTBL34-1 (Figure 3), implying that GhTBL34-2 and GhTBL34-3 were elite alleles that could significantly improve Verticillium wilt (VW) resistance in cotton
The allele GhTBL34-1 mainly appears in susceptible cotton lines, while the alleles GhTBL34-2 and GhTBL34-3 mainly present in resistant cotton lines, and significant differences of disease index between resistant lines carrying GhTBL34-2 and GhTBL34-3 and susceptible lines carrying GhTBL34-1, suggesting that GhTBL34-2 and GhTBL34-3 are elite alleles that could significantly improve

Summary

Introduction

Cotton (Gossypium spp.) is an important economic crop in the world and provides the most important natural fiber for the textile industry. The pathogen of VW usually exists in the soil in the form of microsclerotia and invades the xylem and vascular tissues from the roots of the host plant, expanding to the above-ground parts and leading to leaf chlorosis, necrosis or wilting, leaf and boll abscission, and plant death [2]. One believes that V. dahliae produces a large number of hyphae and conidia after invading the duct tissue cells of cotton, and stimulates the parenchyma cells to produce colloidal substances and intrusion bodies that block the ducts and cause difficulty in transporting water [4]; the other considers that V. dahliae produces some phytotoxic metabolites inducing phytoalexin formation and triggering wilt symptoms associated with disease development [5]. As the first barrier of the pathogen entry into host plants, cell walls play an important role and can effectively resist the invasion of pathogens [9]. The bc, bc6, bc, and bc genes of Arabidopsis mutants were related to the synthesis of cell wall polysaccharides, and the growth of the mutant plants containing the above genes was blocked and showed weakened disease resistance, which proves the importance of polysaccharides in plant growth and disease resistance [11,12,13]

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Conclusion