Brassinosteroids （BRs） are a major group of plant hormones that regulate plant growth and development. BRI1, a protein localized to the plasma membrane, functions as a BR receptor and it has been proposed that its k...Brassinosteroids （BRs） are a major group of plant hormones that regulate plant growth and development. BRI1, a protein localized to the plasma membrane, functions as a BR receptor and it has been proposed that its kinase activity has an essential role in BR-regulated plant growth and development. Here we report the isolation and molecular characterization of a new allele of bril, bril-301, which shows moderate morphological phenotypes and a reduced response to BRs under normal growth conditions. Sequence analysis identified a two-base alteration from GG to AT, resulting in a conversion of 989G to 9891 in the BRI1 kinase domain. An in vitro assay of kinase activity showed that bril-301 has no detectable autophosphorylation activity or phosphorylation activity towards the BRI1 substrates TTL and BAK1. Furthermore, our results suggest that bril-301, even with extremely impaired kinase activity, still retains partial function in regulating plant growth and development, which raises the question of whether BRI1 kinase activity is essential for BR-mediated growth and development in higher plants.展开更多
The present status of studies on regeneration of tomato in vitro was introduced, and the key factors that influence the shoot regeneration system in tomato were summarized, such as genotypes, explants type, explant ph...The present status of studies on regeneration of tomato in vitro was introduced, and the key factors that influence the shoot regeneration system in tomato were summarized, such as genotypes, explants type, explant physiological status, plant hormones and additives. The paper also discussed issues existing in tomato tissue culture and prospected the future development of this system.展开更多
基金We thank Prof Joanne Chory （The Salk Institute for Biological Studies, USA） for providing the Arabidopsis bril-101 mutant seeds. This work was supported by grants from the National Natural Science Foundation of China （grant numbers： 30070074, 30330040 and 30570161）.
文摘Brassinosteroids （BRs） are a major group of plant hormones that regulate plant growth and development. BRI1, a protein localized to the plasma membrane, functions as a BR receptor and it has been proposed that its kinase activity has an essential role in BR-regulated plant growth and development. Here we report the isolation and molecular characterization of a new allele of bril, bril-301, which shows moderate morphological phenotypes and a reduced response to BRs under normal growth conditions. Sequence analysis identified a two-base alteration from GG to AT, resulting in a conversion of 989G to 9891 in the BRI1 kinase domain. An in vitro assay of kinase activity showed that bril-301 has no detectable autophosphorylation activity or phosphorylation activity towards the BRI1 substrates TTL and BAK1. Furthermore, our results suggest that bril-301, even with extremely impaired kinase activity, still retains partial function in regulating plant growth and development, which raises the question of whether BRI1 kinase activity is essential for BR-mediated growth and development in higher plants.
文摘The present status of studies on regeneration of tomato in vitro was introduced, and the key factors that influence the shoot regeneration system in tomato were summarized, such as genotypes, explants type, explant physiological status, plant hormones and additives. The paper also discussed issues existing in tomato tissue culture and prospected the future development of this system.
