Salt-Enhanced Reproductive Development of Suaeda salsa L. Coincided With Ion Transporter Gene Upregulation in Flowers and Increased Pollen K+ Content

Abstract

Halophytes are adapted to saline environments and demonstrate optimal reproductive growth under high salinity. To gain insight into the salt tolerance mechanism and effects of salinity in the halophyte Suaeda salsa , the number of flowers and seeds, seed size, anther development, ion content, and flower transcript profiles, as well as the relative expression levels of genes involved in ion transport, were analyzed in S. salsa plants treated with 0 or 200 mM NaCl. The seed size, flower number, seed number per leaf axil, and anther fertility were all significantly increased by 200 mM NaCl treatment. The Na + and Cl − contents in the leaves, stems, and pollen of NaCl-treated plants were all markedly higher, and the K + content in the leaves and stems was significantly lower, than those in untreated control plants. By contrast, the K + content in pollen grains did not decrease, but rather increased, upon NaCl treatment. Genes related to Na + , K + and, Cl − transport, such as SOS1 , KEA , AKT1 , NHX1 , and CHX , showed increased expression in the flowers of NaCl-treated plants. These results suggest that ionic homeostasis in reproductive organs, especially in pollen grains under salt-treated conditions, involves increased expression of ion transport-related genes.

NaCl improves reproduction by enhancing starch accumulation in the ovules of the euhalophyte Suaeda salsa

“…After excluding low-quality sequences, we used the clean reads to generate a de novo transcriptome assembly using Trinity [46] and analyzed the differences in gene expression between control and NaCl-treated (NaCl) owers after clustering by Corset [47]. The transcripts and genes used in this analysis were described by Guo et al [48].…”

“…Total RNA extraction, library construction, and sequencing Before meiosis (108 DAS), owers were collected from control and NaCl-treated plants. Total RNA extraction and detection were performed as described by Guo et al [48]. Sequencing libraries were generated and processed as described by Hu et al [91].…”

“…Raw reads were cleaned by removing low-quality sequences, sequences containing vector adapter, and poly-N. De novo transcriptome assembly was performed using Trinity [46], and cluster analysis was performed using Corset [47]. The assembled unigenes expressed in S. salsa owers were annotated as described by Guo et al [48].…”

“…DEGs in S. salsa owers from NaCl-treated plants vs. control were analyzed using the DESeq R package (1.10.1). The processing and screening criteria were as described by Guo et al [48].…”

“…To verify the DEGs identi ed by RNA-seq, ten DEGs were randomly selected and subjected to qRT-PCR (quantitative real-time PCR) using speci c primers designed with Beacon Designer software (version 7.0); the primers are listed in additional le 9: Table S3. The procedures and calculations were performed as described in Guo et al [48].…”