Cloning and expression analysis of an E-class MADS-box gene from Populus deltoides

Abstract

An E-class MADS-box gene, PdMADS2, was isolated from Populus deltoides Bartr. ex Marsh male floral buds by RT-PCR. As shown by relative–quantitative real-time polymerase chain reaction analysis, the expression of PdMADS2 was high in apical and floral buds, intermediate in immature xylem and roots and low in mature leaves of adult male P. deltoides. In developing male floral buds, PdMADS2 expression was high and remained constant from July to September, increased significantly on February 6 and quickly fell to a very low level with the maturation of the flowers. In male inflorescences, PdMADS2 expression was abundant in the perianth cups and inflorescence peduncles; it was not detected in mature pollen. In female inflorescences, PdMADS2 was highly expressed in both ovaries and inflorescence peduncles. Our results suggest that PdMADS2 plays an important role in the development of inflorescence meristems and flower organs in poplar.