Benzylaminopurine induces phenocopies of floral meristem and organ identity mutants in wild-typeArabidopsis plants

Abstract

Arabidopsis thaliana (L.) Heynh. has been used as a model system to investigate the regulatory genes that control and coordinate the determination, differentiation and morphogenesis of the floral meristem and floral organs. We show here that benzylaminopurine (BAP), a cytokinin, influences flower development in Arabidopsis and induces partial phenocopies of known floral homeotic mutants. Application of BAP to wild-type inflorescences at three developmental stages results in: (i) increase in floral organ number; (ii) formation of abnormal floral organs and (iii) induction of secondary floral buds in the axils of sepals. These abnormalities resemble the phenotypes of mutants, clv1 (increase in organ number), ap1, ap2, ap3 (abnormal floral organs) and ap1 (secondary floral buds in the axils of first-whorl organs). In addition, BAP induces secondary floral buds in the axils of perianth members of ap2-6, ap3-1 and ag mutants, and accentuates the phenotype of the ap2-1 mutant to resemble the ap2-6 mutant. These observations suggest that exogenous BAP suppresses the normal functioning of the genes for floral meristem identity and thereby affects flower development and the later stages of floral organ differentiation.

Chimeric AGAMOUS repressor induces serrated petal phenotype in Torenia fournieri similar to that induced by cytokinin application

“…The application of N 6 -benzylaminopurine (BA) increased the number of petals in carnation (Jeffcoat 1977) and induced an enlargement of the floral meristem in Arabidopsis (Venglat and Sawhney 1996). In tobacco, expression of endogenous homeotic genes homologous to DEFA, GLO, and PLE of Antirrhinum majus were suppressed when cytokinin content was increased by an ipt-overexpressing transgene (Estruch et al 1993).…”

Characterization ofMdMADS2, a Member of theSQUAMOSASubfamily of Genes, in Apple1

“…Regulation of homeotic gene expression by hormonal or environmental factors has been suggested in several studies (Estruch et al, 1993;Okamuro et al, 1996;Venglat and Sawhney, 1996). It is generally accepted that the development of apple flower buds is the process most sensitive to hormonal, nutritional, and environmental factors, because induction and development of flower buds occur on the trees carrying a heavy crop of fruit (Buban and Faust, 1982;Pratt, 1988).…”

Localized High Expression of Type-A Response Regulator and Cytokinin Oxidase/dehydrogenase Genes in Relation to Forchlorfenuron-induced Changes in Flower Morphology in Torenia fournieri Lind.

“…In Arabidopsis, the number of petals, stamens, and pistils can be increased by application of N 6 -benzylaminopurine (BA) to flower buds (Lindsay et al, 2006;Venglat and Sawhney, 1996). These increases in floral organ numbers are due to the enlarged floral meristem that is caused by cytokininmediated regulation of the genes involved in meristematic activity and organ differentiation, i.e., WUSCHEL 70 and CLAVATA (Bartrina et al, 2011;Clark et al, 1993;Lindsay et al, 2006;Rupp et al, 1999).…”