Genome-Wide Characterization of Lectin Receptor Kinases in Saccharum spontaneum L. and Their Responses to Stagonospora tainanensis Infection.

Zhoutao Wang,Youxiong Que,Liping Xu,Hui Ren,Wei Cheng,Fu Xu,Guilong Lu

doi:10.3390/plants10020322

Abstract

Sugarcane is an important sugar and bioenergy ethanol crop, and the hyperploidy has led to stagnant progress in sugarcane genome decipherment, which also hindered the genome-wide analyses of versatile lectin receptor kinases (LecRKs). The published genome of Saccharum spontaneum, one of the two sugarcane ancestor species, enables us to study the characterization of LecRKs and their responses to sugarcane leaf blight (SLB) triggered by Stagonospora tainanensis. A total of 429 allelic and non-allelic LecRKs, which were classified into evolved independently three types according to signal domains and phylogeny, were identified based on the genome. Regarding those closely related LecRKs in the phylogenetic tree, their motifs and exon architectures of representative L- and G-types were similar or identical. LecRKs showed an unequal distribution on chromosomes and more G-type tandem repeats may come from the gene expansion. Comparing the differentially expressed LecRKs (DELs) in response to SLB in sugarcane hybrid and ancestor species S. spontaneum, we found that the DEL number in the shared gene sets was highly variable among each sugarcane accession, which indicated that the expression dynamics of LecRKs in response to SLB were quite different between hybrids and particularly between sugarcane hybrid and S. spontaneum. In addition, C-type LecRKs may participate in metabolic processes of plant–pathogen interaction, mainly including pathogenicity and plant resistance, indicating their putative roles in sugarcane responses to SLB infection. The present study provides a basic reference and global insight into the further study and utilization of LecRKs in plants.

Highlights

As a leading member of the membrane-anchored pattern-recognition receptors (PRRs) family, receptor kinases (RKs) play crucial roles in perceiving and transmitting diverse signals and stimuli at the cellular level in plants challenged constantly by abiotic and biotic factors [1]
Once the signal domains bind to ligands to form a complex, the intracellular protein kinase domains can be activated via transmembrane domain (TM) and continue to transmit signals to downstream proteins, such as receptor cytoplasmic kinases and MAP kinase (MAPK) cascades [2,5]
Hidden Markov Model (HMM) profiles from each of the six species were used for further search in corresponding species to get lectin receptor kinases (LecRKs) as much as possible

Summary

Introduction

As a leading member of the membrane-anchored pattern-recognition receptors (PRRs) family, receptor kinases (RKs) play crucial roles in perceiving and transmitting diverse signals and stimuli at the cellular level in plants challenged constantly by abiotic and biotic factors [1]. The signals from the environments or other cells, including polypeptides, carbohydrates, steroids and microbial cell-wall components, are transmitted through signal biomolecules [2]. As a super protein family, RKs contain at least 15 subfamily members, with over 600 in Arabidopsis and 1000 in rice [3,4]. Each RK subfamily can recognize one type of signal biomolecules as ligands [2]. Once the signal domains bind to ligands to form a complex, the intracellular protein kinase domains can be activated via transmembrane

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