The optically active chemical 1-α-methylbenzyl-3-p-tolylurea (MBTU) shows diverse properties in plant physiology. The root growth of Cyperus paddy weeds and plants belonging to the tribe Oryzeae are inhibited enantioselectively by R-MBTU. R-MBTU's mode of action is not yet known. Using the PCR-based suppression subtractive hybridization (SSH) technique, we aimed to elucidate the mechanisms by which R-MBTU inhibits root growth of rice (Oryza sativa L.). Forward and reverse subtracted cDNA libraries were obtained after cloning, and these clones were analyzed by quantitative real-time RT-PCR. R-MBTU treatment resulted in down-regulated mRNA levels of several clones; putatively a NADH-dependent glutamate synthase, plastid aspartate aminotransferase, endo-1,4-β-glucanase Cel1, 26S proteasome regulatory subunit S2, and serine/threonine-protein kinase. The mRNA level of a putative histone deacetylase was up-regulated. The putative functions of these clones suggest that root growth inhibition by R-MBTU may be associated with disruption of nitrogen metabolism, amino acid biosynthesis, cellulose synthesis, and cell cycle, and repression of transcription of various genes. We discuss how and which metabolic pathways are affected in the inhibition of root growth with R-MBTU treatment.
ASJC Scopus subject areas