GSE114369
Molecular and Physiological Responses of Citrus sinensis Leaves to Long-term Low pH Revealed by RNA-Seq Integrated with Targeted Metabolomics
Low pH-induced alterations in gene expression profiles and organic acids (OAs) and free amino acids (FAAs) abundances were investigated in Citrus sinensis leaves. We identified 503 downreg-ulated and 349 upregulated genes in low pH-treated leaves. Further analysis indicated that low pH impaired light reaction and carbon fixation in photosynthetic organisms, thereby lowering photosynthesis in leaves. Low pH reduced carbon and carbohydrate metabolisms, OAs biosyn-thesis and ATP production in leaves. Low pH downregulated the biosynthesis of nitrogen com-pounds, proteins and FAAs in leaves, which might be conducive to maintaining energy homeo-stasis during ATP deprivation. Low pH-treated leaves displayed some adaptive responses, in-cluding phosphate recycling, lipid remodeling and phosphate transport. Low pH upregulated the expression of some reactive oxygen species (ROS) and aldehyde detoxifying enzyme (peroxidase and superoxidase) genes and the concentrations of some antioxidants (L-tryptophan, L-proline, nicotinic acid, pantothenic acid and pyroglutamic acid), but it impaired pentose phosphate pathway, VE and secondary metabolite biosynthesis, downregulated the expression of some ROS and aldehyde detoxifying enzyme (ascorbate peroxidase, aldo-keto reductase and 2-alkenal re-ductase) genes and the concentrations of some antioxidants (pyridoxine and ?-aminobutyric acid), thus disturbing the balance between production and detoxification of ROS and aldehydes and causing oxidative damage to leaves. Overall design: Examination of mRNA levels in control and low-pH-treatment leaves of C. sinensis with two-three biological replicates were generated by deep sequencing, using Illumina HiSeq xten device.