Abstract
Class-I TCP transcription factors are plant-specific developmental regulators. Inthis study, the role of one such rice gene, OsTCP19, in water-deficit andsalt stress response was explored. Besides a general upregulation by abioticstresses, this transcript was more abundant in tolerant than sensitive ricegenotypes during early hours of stress. Stress, tissue and genotype-dependentretention of a small in-frame intron in this transcript was also observed.Overexpression of OsTCP19 in Arabidopsis caused upregulation ofIAA3, ABI3 and ABI4 and downregulation of LOX2, andled to developmental abnormalities like fewer lateral root formation. Moreover,decrease in water loss and reactive oxygen species and hyperaccumulation of lipiddroplets in the transgenics contributed to better stress tolerance both duringseedling establishment and in mature plants. OsTCP19 was also shown to directlyregulate a rice triacylglycerol biosynthesis gene in transient assays. Genes similarto those up- or downregulated in the transgenics were accordingly found to coexpresspositively and negatively with OsTCP19 in Rice Oligonucleotide ArrayDatabase. Interactions of OsTCP19 with OsABI4 and OsULT1 further suggest itsfunction in modulation of abscisic acid pathways and chromatin structure. Thus,OsTCP19 appears to be an important node in cell signaling whichcrosslinks stress and developmental pathways.
Role of rice heme oxygenase in lateral root formation
