Comparative phylogenetic analysis of CBL reveals the gene family evolution and functional divergence in Saccharum spontaneum

Xiaomin Feng,Jiayun Wu,Yongwen Qi,Nannan Zhang,Rui Liu,Jisen Zhang,Yonghong Huang,Shuai Gao,Yongjun Wang

doi:10.1186/s12870-021-03175-3

Abstract

BackgroundThe identification and functional analysis of genes that improve tolerance to low potassium stress in S. spontaneum is crucial for breeding sugarcane cultivars with efficient potassium utilization. Calcineurin B-like (CBL) protein is a calcium sensor that interacts with specific CBL-interacting protein kinases (CIPKs) upon plants’ exposure to various abiotic stresses.ResultsIn this study, nine CBL genes were identified from S. spontaneum. Phylogenetic analysis of 113 CBLs from 13 representative plants showed gene expansion and strong purifying selection in the CBL family. Analysis of CBL expression patterns revealed that SsCBL01 was the most commonly expressed gene in various tissues at different developmental stages. Expression analysis of SsCBLs under low K+ stress indicated that potassium deficiency moderately altered the transcription of SsCBLs. Subcellular localization showed that SsCBL01 is a plasma membrane protein and heterologous expression in yeast suggested that, while SsCBL01 alone could not absorb K+, it positively regulated K+ absorption mediated by the potassium transporter SsHAK1.ConclusionsThis study provided insights into the evolution of the CBL gene family and preliminarily demonstrated that the plasma membrane protein SsCBL01 was involved in the response to low K+ stress in S. spontaneum.

Highlights

The identification and functional analysis of genes that improve tolerance to low potassium stress in S. spontaneum is crucial for breeding sugarcane cultivars with efficient potassium utilization
Among the nine SsCBLs, SsCBL01 and SsCBL03 were located on chromosome 1; SsCBL05, SsCBL09, and SsCBL10 were located on chromosome 3; SsCBL04 and SsCBL06 were located on chromosome 7; SsCBL02 was located on chromosome 2, and SsCBL08 was located on chromosome 4
The results revealed that the Ka/Ks value of Calcineurin B-like (CBL) gene pairs between S. spontaneum and S. bicolor was less than 1 (Fig. S2), which suggests that the CBL gene family went through strong purifying selection after the split between S. spontaneum and sorghum, and these genes are functionally conserved

Summary

Introduction

The identification and functional analysis of genes that improve tolerance to low potassium stress in S. spontaneum is crucial for breeding sugarcane cultivars with efficient potassium utilization. Potassium leaching and soil acidification are common in these regions, decreasing the soil potassium content in protein, a plant calcium-binding protein initially identified in Arabidopsis, is a member of a group of small proteins that are strongly homologous with the regulatory B subunit of calcineurin in yeast [2]. The CBL-CIPK complex has an indispensable role in plant response to abiotic stresses such as salinity, potassium starvation, low temperature, and drought [2, 13]. It serves as an important signaling network regulating growth and development, uptake and transport of NO3−, NH4+, and iron, H+ homeostasis, and reactive oxygen species (ROS) signal transduction in plants [13, 14]

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