Genome-Wide Identification and Analyses of Calmodulins and Calmodulin-like Proteins in Lotus japonicas.

Jinqiu Liao,Jiayong Tang,Zongzhi Qin,Ming Yuan,Yonghong Zhou,Ruiwu Yang,Maorong Shu,Jing Liu,Jiabin Deng,Chunbang Ding,Chao Hu,Yan Huang

doi:10.3389/fpls.2017.00482

Jinqiu Liao, Jiayong Tang + Show 10 more

Open Access

https://doi.org/10.3389/fpls.2017.00482

Copy DOI

Abstract

L. japonicus, a model plant of legumes plants, is widely used in symbiotic nitrogen fixation. A large number of studies on it have been published based on the genetic, biochemical, structural studies. These results are secondhand reports that CaM is a key regulator during Rhizobial infection. In plants, there are multiple CaM genes encoding several CaM isoforms with only minor amino acid differences. Moreover, the regulation mechanism of this family of proteins during rhizobia infection is still unclear. In the current study, a family of genes encoding CaMs and CMLs that possess only the Ca2+-binding EF-hand motifs were analyzed. Using ML and BI tree based on amino acid sequence similarity, seven loci defined as CaMs and 19 CMLs, with at least 23% identity to CaM, were identified. The phylogenetics, gene structures, EF hand motif organization, and expression characteristics were evaluated. Seven CaM genes, encoding only 4 isoforms, were found in L. japonicus. According to qRT-PCR, four LjCaM isoforms are involved in different rhizobia infection stages. LjCaM1 might be involved in the early rhizobia infection epidermal cells stage. Furthermore, additional structural differences and expression behaviors indicated that LjCMLs may have different potential functions from LjCaMs.

Highlights

A growing plant is forced to adapt to a variety of external stimuli due to the inconstant nature of its environment
The L. japonicus database was searched with AtCaM1 as the query amino acid sequence using the program BLASTp, and the unfound five sequences (E > 3e-64) were added to the list
The results indicated that LjCML14 and LjCML18 contain a potential myristoylation sequence (Table 2)

Summary

Introduction

A growing plant is forced to adapt to a variety of external stimuli due to the inconstant nature of its environment. To generate specificity in response, Ca2+ signals must be decoded by several Ca2+ sensors or Ca2+-binding proteins, which usually contain a number of paired EF-hand motifs and a helix-loop-helix structure (McCormack et al, 2005; Scholz et al, 2014). Calmodulins and Calmodulin-Like Proteins in Lotus japonicus classes of Ca2+ sensors have been characterized in plants. One class is capable of transducing the signal via enzymatic activity and acts as a Ca2+ sensor or an effecter, such as CDPKs (Ca2+dependent protein kinases), which contain a kinase domain and four EF-hands in a single protein. The primary groups of proteins found in this category include CBLs (calcineurin B-like proteins), CaM (Calmodulins), and CML (calmodulin-like proteins), which only contain EF-hand motif(s) (Yang and Poovaiah, 2003; Scholz et al, 2014)

Methods

Results

Conclusion