主要发现：Here, we verified that QUASIMODO2 (QUA2) is a pectin methyltransferase and determined that QUA2 is required for normal pectin biosynthesis.

研究对象：To gain further insight into how pectin affects wall assembly and integrity maintenance, we investigated cellulose biosynthesis, cellulose organization, cortical microtubules, and wall integrity signaling in two mutant alleles of Arabidopsis thaliana QUA2, qua2 and tsd2. 

结果1：In both mutants, crystalline cellulose content is reduced, cellulose synthase particles move more slowly, and cellulose organization is aberrant.

结果2：NMR analysis shows higher mobility of cellulose and matrix polysaccharides in the mutants.

结果3：Microtubules in mutant hypocotyls have aberrant organization, and depolymerize more readily upon treatment with oryzalin or external force.

结果4：The expression of genes related to wall integrity, wall biosynthesis, and microtubule stability is dis-regulated in both mutants.

结论：These data provide insights into how homogalacturonan is methylesterified upon its synthesis, the mechanisms by which pectin functionally interacts with cellulose, and how these interactions are translated into intracellular regulation to maintain the structural integrity of the cell wall during plant growth and development.