Transcriptome Analyses Reveal Candidate Genes Potentially Involved in Al Stress Response in Alfalfa

Abstract

Alfalfa is the most extensively cultivated forage legume, yet most alfalfa cultivars are not aluminum tolerant, and the molecular mechanisms underlying alfalfa responses to Al stress are largely unknown. In this study, we aimed to understand how alfalfa responds to Al stress by identifying and analyzing Al-stress-responsive genes in alfalfa roots at the whole-genome scale. The transcriptome changes in alfalfa roots under Al stress for 4, 8, or 24 h were analyzed using Illumina high-throughput sequencing platforms. A total of 2464 differentially expressed genes (DEGs) were identified, and most were up-regulated at early (4 h) and/or late (24 h) Al exposure time points rather than at the middle exposure time point (8 h). Metabolic pathway enrichment analysis demonstrated that the DEGs involved in ribosome, protein biosynthesis, and process, the citrate cycle, membrane transport, and hormonal regulation were preferentially enriched and regulated. Biosynthesis inhibition and signal transduction downstream of auxin- and ethylene-mediated signals occur during alfalfa responses to root growth inhibition. The internal Al detoxification mechanisms play important roles in alfalfa roots under Al stress. These findings provide valuable information for identifying and characterizing important components in the Al signaling network in alfalfa and enhance understanding of the molecular mechanisms underlying alfalfa responses to Al stress.

Genome-Wide Identification and Comprehensive Expression Profiling of Ribosomal Protein Small Subunit (RPS) Genes and their Comparative Analysis with the Large Subunit (RPL) Genes in Rice

“…Ribosomal protein genes are important in this context because ribosome constitutes the protein synthesis machinery in a cell and under unfavorable conditions, the composition of the ribosome has been thought to change in order to assist biased protein translation (Wang J. et al, 2013 ). Moreover, some of the Genome-wide RNA sequencing technology and microarray analyses of other crop plants like Sorghum and alfalafa also revealed ribosomal protein genes to be important in response to abiotic stress (Fracasso et al, 2016 ; Liu et al, 2017 ).…”

Genome-Wide Identification of Aluminum-Activated Malate Transporter (ALMT) Gene Family in Rubber Trees (Hevea brasiliensis) Highlights Their Involvement in Aluminum Detoxification

“…Subsequently, RNA purity and concentration were verified with a spectrophotometer (NANODROP 2000c, ThermoScientific, USA). The cDNA library was conducted based on the Illumina manufacturer's instructions [31,32]. The cDNA library was sequenced using Illumina HiseqTM 2000 platform as operated by Guangdong Longsee Biomedical Corporation (Guangzhou, China).…”

Identification of the regulatory networks and hub genes controlling alfalfa floral pigmentation variation using RNA-sequencing analysis

“…Of the above-mentioned Medicago species, purpleflowered alfalfa is the most productive perennial legume with high biomass productivity, an excellent nutritional profile, and adequate persistence [16,17]. Yellow lucerne, which has yellow flowers, is closely related to alfalfa and exhibits better cold tolerance than alfalfa [18,19].…”