iTRAQ-based comparative proteomic analysis of differences in the protein profiles of stems and leaves from two alfalfa genotypes

Abstract

Background To explore the molecular regulatory mechanisms of early stem and leaf development, proteomic analysis was performed on leaves and stems of F genotype alfalfa, with thin stems and small leaves, and M genotype alfalfa, with thick stems and large leaves. Results Based on fold-change thresholds of > 1.20 or < 0.83 (p < 0.05), a large number of proteins were identified as being differentially enriched between the M and F genotypes: 249 downregulated and 139 upregulated in stems and 164 downregulated and 134 upregulated in leaves. The differentially enriched proteins in stems were mainly involved in amino acid biosynthesis, phenylpropanoid biosynthesis, carbon fixation, and phenylalanine metabolism. The differentially enriched proteins in leaves were mainly involved in porphyrin and chlorophyll metabolism, phenylpropanoid biosynthesis, starch and sucrose metabolism, and carbon fixation in photosynthetic organisms. Six differentially enriched proteins were mapped onto the porphyrin and chlorophyll metabolism pathway in leaves of the M genotype, including five upregulated proteins involved in chlorophyll biosynthesis and one downregulated protein involved in chlorophyll degradation. Eleven differentially enriched proteins were mapped onto the phenylpropanoid pathway in stems of the M genotype, including two upregulated proteins and nine downregulated proteins. Conclusion Enhanced chlorophyll synthesis and decreased lignin synthesis provided a reasonable explanation for the larger leaves and lower levels of stem lignification in M genotype alfalfa. This proteomic study aimed to classify the functions of differentially enriched proteins and to provide information on the molecular regulatory networks involved in stem and leaf development.

Effects of Nitrogen Sources on Primary and Secondary Production from Annual Temperate and Tropical Pastures in Southern Brazil

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Noncoding-RNA-Mediated Regulation in Response to Macronutrient Stress in Plants

“…The former detected 28 miRNAs differentially expressed at both 2 days and 10 days after low K stress for two barley genotypes [ 91 ], while the latter found miR9772, miR1120b-3p, miR531, and miR319 displaying differential expression at all time points during the low K treatments, and suggested that these miRNAs were most possibly involved in mediating plant adaptation to K deficiency [ 118 ]. Interestingly, high-throughput sequencing was also employed for identifying differentially expressed miRNAs between two transgenic tomato plants, separately overexpressing SlmiR168a and SlAGO1 , to explore downstream miRNAs (miR171, miR384, miR530, miR858, and miR8007) involved in the SlmiR168 -mediated SlAGO1A regulation upon K stress [ 119 ].…”

Gibberellins Inhibit Flavonoid Biosynthesis and Promote Nitrogen Metabolism in Medicago truncatula

“…Every three individual samples were pooled for one replicate, and three biological replicates were analyzed. Total protein was isolated and purified according to a previously published study [90]. Additionally, protein concentration was measured using a Bradford assay kit (Bio-Rad Laboratories Inc., Hercules, CA, USA), and bovine serum albumin (BSA) was used as a reference protein for this experiment to generate a standard curve.…”