Effect of 1-aminocyclopropane-1-carboxylic acid (ACC)-induced ethylene on cellulose synthase A (CesA) genes in flax (Linum usitatissimum L. 'Nike') seedlings.

ABSTRACT

INTRODUCTION: Cellulose microfibril is a major cell wall polymer that plays an important role in the growth and development of plants. The gene cellulose synthase A (CesA), encoding cellulose synthases, is involved in the synthesis of cellulose microfibrils. However, the regulatory mechanism of CesA gene expression is not well understood, especially during the early developmental stages. OBJECTIVE: To identify factor(s) that regulate the expression of CesA genes and ultimately control seedling growth and development. METHODS: The presence of cis-elements in the promoter region of the eight CesA genes identified in flax (Linum usitatissimum L. 'Nike') seedlings was verified, and three kinds of ethylene-responsive cis-elements were identified in the promoters. Therefore, the effect of ethylene on the expression of four selected CesA genes classified into Clades 1 and 6 after treatment with 10-4 and 10-3 M 1-aminocyclopropane-1-carboxylic acid (ACC) was examined in the hypocotyl of 4-6-day-old flax seedlings. RESULTS: ACC-induced ethylene either up- or down-regulated the expression of the CesA genes depending on the clade to which these genes belonged, age of seedlings, part of the hypocotyl, and concentration of ACC. CONCLUSION: Ethylene might be one of the factors regulating the expression of CesA genes in flax seedlings.