Poster: Root Biology

Abs # 525: High temperature rescues the defect in root elongation of a conditional root mutant in rice (Oryza sativa L.)

Presenter:	Wang, Hua , s00x615@stmail.ag.kagawa-u.ac.jp
Authors	Wang, Hua  (A)   Taketa, Shin  (A)   Ichii, Masahiko  (A)
Affiliations:	(A): Faculty of Agriculture, Kagawa University

Plant growth and development are regulated by both endogenous regulators and external environmental factors, such as light and temperature. However, the mechanisms underlying plant developmental process regulated by environmental factors are still unclear. In this study, we isolated a rice mutant, LMH9 which shows about 40% of root length of wild type (Oryza sativa L. ssp. japonica cv. Oochikara) when grown in distilled water for 7 days after sowing at 25¡æ. Genetic analysis indicated that the short root phenotype in LMH9 was controlled by a single recessive gene, which was not allelic to any of short-root genes reported previously in rice. A remarkable characteristic of LMH9 mutant is that 7-day-old LMH9 seedlings exhibited the same root length as that of wild-type when grown in distilled water at a high temperature (32¡æ) after germination, indicating that the high temperature can rescue the defect in root elongation in LMH9. We also demonstrated that this temperature-induced root elongation is independent of light conditions. In addition to temperature sensitivity, LMH9 mutant showed a conditional root phenotype depending on culture methods. In soil culture at 25¡æ, the reduced root length of LMH9 seedlings disappeared, implying that the defect in root elongation in LMH9 mutant was probably due to nutrient deficiency. Based on these observations, it is likely that the mutation in LMH9 would provide a useful example for studying the interactions between short-root genes and environmental factors.