Increased Polyamine Biosynthesis Enhances Stress Tolerance by Preventing the Accumulation of Reactive Oxygen Species: T-DNA Mutational Analysis of Oryza sativa Lysine Decarboxylase-like Protein 1

Abstract

A highly oxidative stress-tolerant japonica rice line was isolated by T-DNA insertion mutation followed by screening in the presence of 50 mM H 2 O 2 . The T-DNA insertion was mapped to locus Os09g0547500, the gene product of which was annotated as lysine decarboxylase-like protein (GenBank accession No. AK062595). We termed this gene OsLDC-like 1, for Oryza sativa lysine decarboxylase-like 1. The insertion site was in the second exon and resulted in a 27 amino acid N-terminal deletion. Despite this defect in OsLDC-like 1, the mutant line exhibited enhanced accumulation of the polyamines (PAs) putrescine, spermidine, and spermine under conditions of oxidative stress. The generation of reactive oxygen species (ROS) in the mutant line was assessed by qRT-PCR analysis of NADPH oxidase (RbohD and RbohF), and by DCFH-DA staining. Cellular levels of ROS in osldc-like 1 leaves were significantly lower than those in the wild-type (WT) rice after exposure to oxidative, high salt and acid stresses. Exogenouslyapplied PAs such as spermidine and spermine significantly inhibited the stress-induced accumulation of ROS and cell damage in WT leaves. Additionally, the activities of ROS-detoxifying enzymes were increased in the homozygous mutant line in the presence or absence of H 2 O 2 . Thus, mutation of OsLDC-like 1 conferred an oxidative stress-tolerant phenotype. These results suggest that increased cellular PA levels have a physiological role in preventing stress-induced ROS and ethylene accumulation and the resultant cell damage.

Osa‐miR398b boosts H2O2 production and rice blast disease‐resistance via multiple superoxide dismutases

“…NADPH oxidase is the key enzyme catalyzing the production of O • 2 − (Kaur et al ., ). We then monitored the mRNA amounts of three NADPH oxidase genes, RbohB (Nagano et al ., ), RbohD and RbohF (Jang et al ., ). Guy11 infection clearly decreased their RNA amounts in all three WT rice varieties – Kasalath, NPB and TP309.…”

“…In Arabidopsis, both RbohD and RbohF are required for ROS production, as atrbohD and atrbohF mutants show lower ROS concentrations during incompatible interactions with bacterial and oomycete pathogens (Torres et al, 2002). In rice, RbohD and RbohF are induced by oxidative stress, leading to increased intracellular ROS accumulation (Jang et al, 2012). RbohB knockdown rice plants display enhanced susceptibility to rice blast fungus Magnaporthe oryzae, suggesting that RbohB is required for resistance to rice blast (Nagano et al, 2016).…”

Overexpression of S‐adenosyl‐l‐methionine synthetase increased tomato tolerance to alkali stress through polyamine metabolism

“…Jang et al . () found that the osldc like‐1 rice mutant line had a higher tolerance to abiotic stress by preventing the accumulation of ROS. Additionally, the mutant lines PAs accumulations were significantly increased, showing that increased endogenous PAs biosynthesis was an effective strategy to enhance crops tolerance to abiotic stress.…”

Effect of biogenic polyamine spermine on the structure and function of photosystem I

“…Also, they can preserve the thylakoid membranes integrity and function under stress condition [50]. On the other hand, this stabilization may be due to the antioxidant character of Spm [51][52][53]. Indeed, the presence of the tetra-amine at or near the site of ROSs generation (FA and FB located on PsaC) likely favoured the ROSs scavenging before they damage the PSI polypeptides.…”