Genome-Wide Analysis of TIR-NBS-LRR Gene Family in Potato Identified StTNLC7G2 Inducing Reactive Oxygen Species in Presence of Alternaria solani.

Namo Dubey,Anjali Chaudhary,Kunal Singh

doi:10.3389/fgene.2021.791055

Abstract

Resistance gene analogs (RGAs) comprising NBS-LRR gene family members are considered prominent candidates in the development of disease-resistant genotypes. NBS-LRR gene family comprised a very large number of genes; therefore, members of one subfamily TIR-NBS-LRR (TNL) are identified in the present study from Solanum tuberosum genome, followed by their bioinformatics characterization. The study identified a total of 44 genes encoding 60 TNL transcripts with two prominent clusters at chromosome 1 and chromosome 11. Expression analysis of 14 TNL genes after Alternaria solani infection at 1, 2, 3, 5, and 7 days post inoculation in two disease-tolerant varieties, Kufri Jyoti and Kufri Pukhraj, and one relatively susceptible variety, Kufri Chandramukhi, showed differential expression of many genes including a high expression (>15-fold) of StTNLC6G2T1 and StTNLC11G9T1. Functional characterization of one such gene, StTNLC7G2, reveals involvement in the generation of reactive oxygen species under A. solani attack, implicating its putative role in plant defense via hypersensitive response.

Highlights

Phytopathogens are microbes that have developed the capacity to suppress and overcome the host immune responses and inhabit the plant tissue for their survival, growth, and even multiplication (Chisholm et al, 2006)
Among the three varieties used in the experiments, Kufri Jyoti (KJ) and Kufri Pukhraj (KP) have been previously released as blight disease-tolerant varieties, while Kufri Chandramukhi (KC) is considered more susceptible to blight diseases of potatoes
As there is always a possibility to skip the detection of the targeted domain by hidden Markov model (HMM) profile due to partial or truncated sequences, a second strategy of conserved domain (CD) search using the entire proteome set from the PGSC database was submitted on the National Center for Biotechnology Information (NCBI) CD database (CDD) search engine

Summary

Introduction

Phytopathogens are microbes that have developed the capacity to suppress and overcome the host immune responses and inhabit the plant tissue for their survival, growth, and even multiplication (Chisholm et al, 2006). Members of the NBS-LRR family are one such class of proteins consisting of an N-terminal CC or TIR domain, central NBS domain, and LRR motifs at C-terminal (Mchale et al, 2006) These proteins, known as resistance gene analogs (RGAs), have been studied extensively in many plant systems with delineation of their role against a variety of pathogens including fungal, viral, nematode, and bacterial species (Dubey and Singh, 2018). Plants’ innate immunity is the first line of defense response to pathogen attack by recognition of pathogen-associated molecular patterns (PAMPs) by plant recognition receptors (PRRs) (Jones and Dangl, 2006) This is followed by the induction of reactive oxygen species (ROS) known as hypersensitive response (HR) and recognition of pathogenassociated virulence factors and effectors by members of the NBS-LRR protein family.

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Discussion

Conclusion