Preliminary Study Of The Low Temperature Sensitive Mutant Lts1

Plant root system is the organ for absorbing water and nutrients.Lateral roots (LR)are important components for establishment of root system.Little is known about molecular mechanisms and key genes for lateral root development in rice.By screening a rice EMS-generated mutant library(Kasalath,indica),we isolated a lateral root mutant with low temperature sensitivty,designated as lts1(low temperature sensitive 1).The physiological,phenotypic,and genetic characterizations of lts1 were investigated.The results are summarized as follows:1.lts1 mutant defects in lateral root primordial(LRP)formation at low temperature (below 25℃)and also showed growth inhibition.At 32℃there was no significantly different growth performance between the mutant and the wild-type seedlings,lts1 mutant and the wild type plants grew at 30℃/22℃(day/night)before the maturation period and then grew at 25℃until anthesis.Pollen staining showed that pollen activity in lts1 mutant was not been reduced.Observation of morphology at mature stage showed that the reproduction and development of lts1 mutant have been impacted at 30℃/22℃(day/night),the tiller number,seed fertility and length of spike of the mutant were reduced.2.The nitrogen and phosphate starvation experiments showed no significant phenotypic difference between the mutant and the wild-type seedlings,except the number of lateral root at 28℃and 32℃.The number of lateral root reduced in lts1 mutant but increased in the wild-type,lts1 mutant showed similar response with the wild type to different concentrations of NAA,6-BA,ACC and ABA at different temperatures.3.Genetic analysis with a reciprocal cross between lts1 mutant and the wild-type plants indicated that lts1 possessed a semi-dominant mutation in a single nuclear locus.Map-based cloning revealed that LTS1 gene was linked to a STS maker (STS1-1)on chromosome one.