Abstract
A temperature-sensitive mutant of Arabidopsis, lignescens (lig), was characterized by growth defects associated with aberrant lignification at higher temperatures. Whereas the lig seedlings grew normally at 18C, their root growth was inhibited at 28C. Lignin contents of lig started to increase 2 days after temperature shift to 28C and aberrant lignification occurred in the root sub-apical region. Although an inhibitor of lignin synthesis, AIP, inhibited aberrant lignification in the lig mutants at 28C, it did not restore their root growth. Evans blue staining detected cell death in root hairs of lig at 28C. We investigated effects of the lig mutation on expression patterns of lignification-related and some other genes; AtPAL1, AtCAD-D, AtCCR1, AtCCR2, AtVSP1, AtPDF1.2, AtCESA1 and AtCESA3. Exposure of lig to 28C increased the expression of AtPAL1, AtCAD-D, AtCCR2, and AtPDF1.2. Based on these results, mechanisms of aberrant lignification and growth defects in the lig mutant will be discussed.
