Comparative proteomic analysis identified proteins and the phenylpropanoid biosynthesis pathway involved in the response to ABA treatment in cotton fiber development.

Abscisic acid (ABA) is a plant hormone that plays an important role in cotton fiber development. In this study, the physiological changes and proteomic profiles of cotton (Gossypium hirsutum) ovules were analyzed after 20 days of ABA or ABA inhibitor (ABAI) treatment. The results showed that compared to the control (CK), the fiber length was significantly decreased under ABA treatment and increased under ABAI treatment. Using a tandem mass tags-based quantitative technique, the proteomes of cotton ovules were comprehensively analyzed. A total of 7321 proteins were identified, of which 365 and 69 differentially accumulated proteins (DAPs) were identified in ABA versus CK and ABAI versus CK, respectively. Specifically, 345 and 20 DAPs were up- and down-regulated in the ABA group, and 65 and 4 DAPs were up- and down-regulated in the ABAI group, respectively. The DAPs in the ABA group were mainly enriched in the biosynthesis of secondary metabolites, phenylpropanoid biosynthesis and flavonoid secondary metabolism, whereas the DAPs in the ABAI group were mainly enriched in the indole alkaloid biosynthesis and phenylpropanoid biosynthesis pathways. Moreover, 9 proteins involved in phenylpropanoid biosynthesis were upregulated after ABA treatment, suggesting that this pathway might play important roles in the response to ABA, and 3 auxin-related proteins were upregulated, indicating that auxin might participate in the regulation of fiber development under ABAI treatment.

Identification and functional analysis of the CorA/MGT/MRS2-type magnesium transporter in banana.

Magnesium (Mg) plays an irreplaceable role in plant growth and development. Mg transporters, especially CorA/MGT/MRS2 family proteins, played a vital role in regulating Mg content in plant cells. Although extensive work has been conducted in model crops, such as Arabidopsis, rice, and maize, the relevant information is scarce in tropical crops. In this study, 10 MaMRS2 genes in banana (Musa acuminata) were isolated from its genome and classified into five distinct clades. The putative physiochemical properties, chromosome location, gene structure, cis-acting elements, and duplication relationships in between these members were analyzed. Complementary experiments revealed that three MaMRS2 gene members (MaMRS2-1, MaMRS2-4, MaMRS2-7), from three distinct phylogenetic branches, were capable of restoring the function of Mg transport in Salmonella typhimurium mutants. Semi-quantitative RT-PCR showed that MaMRS2 genes were differentially expressed in banana cultivar 'Baxijiao' (Musa spp. AAA Cavendish) seedlings. The result was confirmed by real-time PCR analysis, in addition to tissue specific expression, expression differences among MaMRS2 members were also observed under Mg deficiency conditions. These results showed that Mg transporters may play a versatile role in banana growth and development, and our work will shed light on the functional analysis of Mg transporters in banana.

Proteomic analysis reveals that sugar and fatty acid metabolisms play a central role in sterility of the male-sterile line 1355A of cotton.

Cotton (Gossypium spp.) is one of the most important economic crops and exhibits yield-improving heterosis in specific hybrid combinations. The genic male-sterility system is the main strategy used for producing heterosis in cotton. To better understand the mechanisms of male sterility in cotton, we carried out two-dimensional electrophoresis (2-DE) and label-free quantitative proteomics analysis in the anthers of two near-isogenic lines, the male-sterile line 1355A and the male-fertile line 1355B. We identified 39 and 124 proteins that were significantly differentially expressed between these two lines in the anthers at the tetrad stage (stage 7) and uninucleate pollen stage (stage 8), respectively. Gene ontology-based analysis revealed that these differentially expressed proteins were mainly associated with pyruvate, carbohydrate, and fatty acid metabolism. Biochemical analysis revealed that in the anthers of line 1355A, glycolysis was activated, which was caused by a reduction in fructose, glucose, and other soluble sugars, and that accumulation of acetyl-CoA was increased along with a significant increase in C14:0 and C18:1 free fatty acids. However, the activities of pyruvate dehydrogenase and fatty acid biosynthesis were inhibited and fatty acid ß-oxidation was activated at the translational level in 1355A. We speculate that in the 1355A anther, high rates of glucose metabolism may promote fatty acid synthesis to enable anther growth. These results provide new insights into the molecular mechanism of genic male sterility in upland cotton.