Genetic variation and gene expression of anthocyanin synthesis and transport related enzymes in Oryza sativa against thiocyanate.

Plants exposed to environmental contaminants often synthesize anthocyanins (ATHs) as an approach to safeguard themselves from adverse impact. However, the overload of ATHs in plant cells can threaten their growth and development through proteins oxidization and intercalating with DNAs inside cells. In the present study, a microcosm hydroponic experiment was conducted using rice seedlings to investigate the molecular signaling pathways involved in regulating and controlling ATHs synthesis and transport exposed to thiocyanate (SCN-). Our results indicated that SCN- exposure significantly (p < 0.05) increased the expression of ATHs synthesis related genes (i.e., PAL, CHS, ANS, UFGT genes) in rice tissues, altered the activities of these ATHs synthesis related enzymes, and consequently elevated the ATHs content. However, SCN- exposure significantly decreased the expression of ATHs transport related genes (i.e., GST, ABC, MATE genes) in rice seedlings, suggesting that SCN- exposure have restrained ATHs transport from cytosol to vacuole in cells, eventually posing a significant adverse effect on cells survival. Our findings highlight on one of the plant aspects in managing the toxicity triggered by secondary metabolites under stress conditions.

mRNA Analysis of Genes Encoded with Phytochelatin Synthase (PCS) in Rice Seedlings Exposed to Chromium: The Role of Phytochelatins in Cr Detoxification.

Transcriptional changes of genes encoded with phytochelatins synthase (PCS) was investigated in rice seedlings exposed to potassium chromate Cr(VI) or chromium nitrate Cr(III) using qRT-PCR. Our study demonstrates that both Cr variants initiated different responses of phytochelatin content and PCS activities in rice tissues. Six putative PCS genes were expressed differentially in response to both Cr species. Comparing gene expression between root/shoots, only LOC_Os05g34290.1 and LOC_Os06g01260.1 genes were expressed in similar patterns in Cr(VI) treatment, while none of them were expressed equally in Cr(III) treatments. Inconsistent expression of PCS genes in two Cr variants as well as in rice tissues were most likely related to its individual chemical properties and chemical speciation. Results presented here indicate that the role of phytochelatins in Cr detoxification between two Cr variants in rice was different and six putative PCS genes functioned differently in stimulating PCS activities and regulating phytochelatin formation.