Molecular Cloning, Characterization, and Expression Analysis of SIMILAR TO RCD-ONE (SRO) Family Genes Responding to Abiotic and Biotic Stress in Cucumber

Abstract

SIMILAR TO RCD-ONE (SRO) is a plant-specific small protein family that controls many biological processes including physiological development and stress responses. The SRO gene family has been studied in several plant species, but no detailed characterization and expression profiles of this important gene family were performed in cucumber. In this study, we characterize the SRO genes in cucumber, and determined their transcript levels in various tissues and under exposure to diverse biotic and abiotic stressors. Four SRO genes (named as CsSRO1–CsSRO4) were identified and isolated, which were distributed on three different chromosomes. Gene duplication analysis showed that only one pair of segmental duplication event was identified, but no tandem duplication events were detected. All CsSROs consist of the PARP domain and a C-terminal RST domain, while the N-terminal WWE domain was only present in CsSRO2 and CsSRO4. SROs from 15 plant species are divided into two groups (I and II), and group I can be further divided into four subgroups (Ia to Id) according to the phylogenetic tree. The conserved motif and gene structure analyses showed that SROs within the same branch of the phylogenetic tree have analogous conserved motifs configuration and gene structures. However, SRO genes possessed variable numbers of introns in different subgroups, which may affect the evolution of new family members. RNA-Seq data and qRT-PCR results showed that the four CsSRO genes have distinct expression pattern in various tissues and under diverse stresses, suggesting their multiple functions in plant growth and stress responses. The findings provide a basis for further research aiming at functional characterization of the regulatory mechanism to reveal the roles of CsSRO genes in developmental and stress-related processes of cucumber.

Genome-Wide Analysis of SIMILAR TO RCD ONE (SRO) Family Revealed Their Roles in Abiotic Stress in Poplar

“…To date, AtSRO4 may be involved in transduction for stress, and AtSRO5 is required for the oxidative stress response and in response to salt treatment [ 13 , 14 ]. There have been extensive studies of SROs in other plant species [ 15 ]. For example, SNAC1 and DST interact directly with OsSRO1c in rice to regulate stomatal closure and accumulate hydrogen peroxide in response to drought and oxidative stress [ 16 ].…”