Genome-wide analysis of OSCA gene family members in Vigna radiata and their involvement in the osmotic response

Abstract

Background Mung bean (Vigna radiata) is a warm-season legume crop and belongs to the papilionoid subfamily of the Fabaceae family. China is the leading producer of mung bean in the world. Mung bean has significant economic and health benefits and is a promising species with broad adaptation ability and high tolerance to environmental stresses. OSCA (hyperosmolality-gated calcium-permeable channel) gene family members play an important role in the modulation of hypertonic stress, such as drought and salinity. However, genome-wide analysis of the OSCA gene family has not been conducted in mung bean. Results We identified a total of 13 OSCA genes in the mung bean genome and named them according to their homology with AtOSCAs. All the OSCAs were phylogenetically split into four clades. Phylogenetic relationship and synteny analyses showed that the VrOSCAs in mung bean and soybean shared a relatively conserved evolutionary history. In addition, three duplicated VrOSCA gene pairs were identified, and the duplicated VrOSCAs gene pairs mainly underwent purifying selection pressure during evolution. Protein domain, motif and transmembrane analyses indicated that most of the VrOSCAs shared similar structures with their homologs. The expression pattern showed that except for VrOSCA2.1, the other 12 VrOSCAs were upregulated under treatment with ABA, PEG and NaCl, among which VrOSCA1.4 showed the largest increased expression levels. The duplicated genes VrOSCA2.1/VrOSCA2.2 showed divergent expression, which might have resulted in functionalization during subsequent evolution. The expression profiles under ABA, PEG and NaCl stress revealed a functional divergence of VrOSCA genes, which agreed with the analysis of cis-acting regulatory elements in the promoter regions of VrOSCA genes. Conclusions Collectively, the study provided a systematic analysis of the VrOSCA gene family in mung bean. Our results establish an important foundation for functional and evolutionary analysis of VrOSCAs and identify genes for further investigation of their ability to confer abiotic stress tolerance in mung bean.

Genome-Wide Identification and Expression Profile of OSCA Gene Family Members in Triticum aestivum L.

“…Current research suggests that OSCA family members act as osmotic sensors to mediate the increase in intracellular Ca 2+ concentration induced by hyperosmolality and control the closure of stomata in the process of immune signal transduction [ 15 , 25 ]. In view of the importance of the functions of OSCA family members, they have been systematically identified in several species, including A. thaliana , rice, maize, and Vigna radiata (L.) [ 15 , 16 , 17 , 18 ] but not so far in wheat. In this study, 42 OSCA members were identified using T. aestivum genomic data, and the expression patterns of 15 members in different tissues and under three abiotic stress treatments were analyzed.…”

“…The number of OSCAs in the T. aestivum genome is more than that of A. thaliana , rice, maize, and Vigna radiate [ 15 , 16 , 17 , 18 ], perhaps in part because the T. aestivum genome is larger. Phylogenetic analysis showed that TaOSCAs fall into four clades ( Figure 1 ), consistent with the topology of the phylogenetic tree of A. thaliana OSCA members [ 15 ].…”

“…For quantitative PCR expression analysis, T. aestivum seedlings (YangMai 158, shared by Professor Jian Yang from Ningbo University) were raised in potting compost under the following controlled conditions: temperature 23 ± 1 °C; 16 h day/8 h night; and relative humidity 60%. Seedlings at the three-leaf stage were treated with 20% ( w/v ) PEG-6000, NaCl (100 mM), ABA (100 μM), or 0.1% Triton X-100 (control) [ 17 , 40 ]. After the stress treatment, leaves were collected at different time points, quickly frozen in liquid nitrogen, and stored at −80 °C.…”

“…An osca1.1 mutant had impaired osmotic calcium signal transmission in guard cells and root cells and impaired regulation of water transpiration and root growth in response to osmotic stress, indicating that osca1.1 may be an osmosensor in A. thaliana [ 15 ]. OSCA1.1 belongs to a 15-member gene family in A. thaliana , and homologous genes are found in other plant species and eukaryotes [ 16 , 17 , 18 ]. Studies on functional domains indicate that the OSCA gene family encodes a calcium-dependent channel domain (DUF221) [ 14 ].…”

“…OSCA family members thus play a vital role in plant resistance to high osmotic stress and other stimuli. The OSCA gene family has been systematically identified and analyzed in A. thaliana [ 14 , 15 ], rice [ 16 ], maize [ 18 ], and Vigna radiate L. [ 17 ] but not so far in wheat ( Triticum aestivum L.), globally one of the most widely grown crops [ 26 ]. To explore whether the wheat OSCA gene family has a function in the process of regulating abiotic stress response, we conducted a genome-wide identification of T. aestivum OSCA family members and analyzed their phylogenetic relationships and expression profiles under different tissues and different abiotic stresses in this study.…”