The isolation and characterization of an Arabidopsis mutant mutagenized by low-energy ion beam

A screen for Arabidopsis fertility mutants, mutagenized by low-energy ion beam, yields two partial male-sterile mutants tc243-1 and tc243-2 that have similar phenotype. And tc243-2 is investigated in detail. Gene mapping and complementation testing indicate that it is allelic to auxin-signaling mutant axr1. A repetitive insertion of “TTATA” in + 624 bp of tc243 leads to premature AXR1. tc243 has severe morphological defects in leaf, plant height, inflorescence and flower morphology. The developmental defects in stamen directly result in the partial male sterility in tc243. In addition, as a strong mutant allele of axr1, tc243 is more insensitive to auxin than axr1-3, a weak allele of axr1. However, the root growth of tc243 is more inhibited by MeJA than that of axr1-3. These results suggest that flower development and root growth can be regulated by different downstream pathways of AXR1-mediated jasmonate signaling, and that the inactivity of AXR1 can lead to the increasing efficiency of AXL1-mediated jasmonate signaling.