MULTIPLE AUXIN RESPONSE MODULES IN THE SOYBEAN SAUR 15A PROMOTER

The soybean SAUR genes are primary auxin response genes that are induc ed within a few minutes after auxin application. It has been previousl y shown that a small region (referred to as the DUE/NDE element) in th e SAUR 15A promoter is sufficient to confer auxin responsiveness [Li e t al., Plant Physiol 106 (1994) 37-43]. Here, we describe a second aux in response region of 47-bp in the SAUR 15A promoter that resides upst ream of the DUE/NDE element. We also report on site-directed mutations in the NDE/DUE element that suggest a complex organization for this a uxin-response element. Our results indicate that the SAUR 15A promoter is composed of multiple auxin response elements that behave different ly than those previously characterized in the soybean GH3 promoter [Li u et al. Plant Cell, 6 (1994) 645-657]. (C) 1997 Elsevier Science Irel and Ltd.