POSITIVE REGULATION OF PHYTOCHROME A ON SHADE AVOIDANCE IN MAIZE

Shade avoidance is elongation, apical dominance and some other responses of plants adapting to deficiency light intensity. The spindling plants are susceptible to lodging, resulting in productivity and quality decline. Many studies have indicated the effect of phytochrome B as the predominant photoreceptor for negative regulation of shade avoidance. The role of phytochrome A on shade avoidance has not yet been clarified in detail. In this study, we overexpressed ZmPhyAl gene in maize inbred line 18-599. The T-DNA integration site was found out between the 284557834th and the 284557835th bp of chromosome 1 by genome walking amplification. The plant height, ear height, and leaf length under ear of the transgenic line was significantly higher or longer than the receptor line. Leaf angle under ear was significantly less. These phenotypes were concluded as the positive regulation of the ZmPhyAl gene to shade avoidance of the receptor line, because no sequence similar to any functional genes, repeated sequences or transposons were found from the flanking sequences from 46 kb upstream to 314 kb downstream of the T-DNA integration site. Therefore, expression suppression of the ZmPhyAl gene could be employed for photo-biotechnological improvement for dense planting variety.