Abstract
We have identified a rice mutant, fish bone (fib), which exhibits pleiotropic abnormalities in most of above- and under-ground organs. fib plants show abnormal phyllotaxy, disrupted vascular systems, aberrant floral organs, reduced numbers of crown roots and lateral roots, agravitropism and so on. The wild type plants treated with polar auxin transport (PAT) inhibitor mimicked most of the fib phenotypes, suggesting that fib has defects in PAT. Then, we have measured PAT activities in root and inflorescence stem. The results indicate that PAT activity is impaired in fib plants. In addition, fib plants also show reduced auxin contents and increased auxin sensitivity, but detailed analyses suggest that these are secondary effects caused by PAT defects. Thus, many abnormalities in fib are caused by defects in PAT. The FIB gene encodes novel factor, and it would play important and novel roles in controlling PAT.
