An appropriate concentration of arginine is required for normal root growth in rice

Abstract

Plant roots play an important role in uptake of water and nutrients, support of above-ground part and environmental sensing, but the molecular mechanisms underlying the root development are poorly understood in rice. We found that a gene (OsASL1) encoding argininosuccinate lyase is involved in normal root development of rice. OsASL1 cleaves argininosuccinate to arginine and fumarate reversibly, the last step in the arginine biosynthetic pathway. Here, we further characterized OsASL1 in terms of expression pattern, subcellular localization, and arginine effect on the root growth. A detailed expression analysis revealed that 2 transcripts of OsASL1, OsASL1.1 and OsASL1.2, showed different expression patterns; OsASL1.1 was expressed in most organs throughout the whole growth period, whereas OsASL1.2 was mainly expressed in the roots. In contrast to plastid-localized OsASL1.1, OsASL1.2 was localized to the cytosol and nucleus. The short-root phenotype of the mutant was not rescued by exogenous addition of the sodium nitroprusside, a nitric oxide donor, but rescued by an appropriate concentration of Arg. Our results indicate that the subcellular localization was determined by the N terminus of OsASL1 and that appropriate concentration of Arg is required for normal root elongation in rice.

Physiological implications of arginine metabolism in plants

“…A characterization of the Arabidopsis ASL (At5g10920) is also still missing. The rice ASL mutant osred1 showed a short root phenotype like the Arabidopsis NAOAT mutant tup5-1 , supporting the suggestion that arginine is essential for normal root growth in different plant species ( Frémont et al, 2013 ; Xia et al, 2014a , b ). Expression analysis revealed two alternatively spliced transcripts of OsASL1 , OsASL1.1 , and OsASL1.2 , coding for two ASL isoforms with slightly different N-termini.…”

“…Only OsASL1.1 showed ASL activity in a yeast complementation study. The short-root phenotype of the osred1 mutant was rescued by external arginine supply but not by a NO donor, supporting the hypothesis that arginine is required for normal root growth independently of its function as putative NO precursor ( Xia et al, 2014a , b ). The poplar ASL homolog was the only gene, among 17 analyzed genes of arginine metabolism in poplar, whose expression was higher in response to putrescine overproduction in a transgenic line.…”

A high-quality sponge gourd (Luffa cylindrica) genome

“…Phosphorus plays crucial roles in plant growth and development by regulating plant hormone transport 31 , 32 . Furthermore, arginine is important for the development of plants (especially root systems) 33 and is the precursor for the synthesis of endogenous hormone polyamines, thus improving tolerance to high salinity and other stress conditions 34 , 35 ; these roles are consistent with the enrichment of specific and expanded gene families in genes involved in the defense response (Supplementary Tables S 11 and S 12 ). These results indicate the genomic changes that underlie the value of sponge gourd as a traditional edible vegetable.…”

Systems strategies for developing industrial microbial strains

“…The end market for l-arginine was identified as for non-food, non-animal feed applications, such as for use as a plant growth stimulant 68 , thus the use of a genetically modified C. glutamicum strain was considered acceptable. The preferred carbon substrates were derived from glucose and/or sucrose from industrially relevant feedstocks, corn starch hydrolysate and/or decomposed raw sugar from sugarcane.…”