Legume Model Plant Lotus Corniculatus Biological Function Of Tcp Domain And Petal Development

Legume floral development system has been established successfully based on Lotus japonocus — the model plant in legume. Using Scanning Electronic Microscope (SEM), the development process of Lotus japonicus (Gifu) was divided into different stages accurately, including inflorescence development, floral development and petal development.TCP domain genes are the key developmental control genes existing in many species. The different member in different species involved in various morphology development processes. In this study we analyzed the expression pattern and biological function of Ljcyc1 and Ljcyc2, two TCP domain genes in Lotus japonocus .RNA in situ hybridization shows that, Ljcyc1 firstly express in the flank of SAM (vegetative) and I, (reproductive). At the floral development stage 1, Ljcyc1 express in the dorsal region and the central region simultaneously. Then, the region and intention of Ljcyc1 expression increase. At the floral development stage 7, Ljcyc1 is detected strongly in carpel and dorsal petal.Ljcyc2 is firstly detected at the flank of I₁ apical meristem before I₂ initiation. Then, Ljcyc2 express in the junction of I1 and I2. Since inflorescence development stage 4, Ljcyc2 is detected at the apex of I₂, and this expression was maintained to the initiation of floral primordia. Following the initiation of floral primordia (Floral development stage 1) , Ljcyc2 express in the dorsal region of the floral meristem. Along with the floral meristem development, Ljcyc2 expression increases into the whole dorsal region without carpel primordia. Since floral development stage 5, Ljcyc2 mainly express in the dorsal sepal and petal. At the late stage of floral development, Ljcyc2 expression is strongly detected in the dorsal petal. The analysis of Ljcyc2 transgenic plants suggest that Ljcyc2 not only involve in establishment of dorsal-ventral polarity in the development of flower, but also involve in inflorescence structure, which is consistent with its expression pattern in I₁. It is the first time to report that TCP domain gene has a new function in controlling inflorescence development and structure, which will help us to understand the diversity of the function of TCP domain genes in plant.Furthermore, a kind of keeled wing mutation has been analyzed in genetics and morphology. The results showed that kw1, kw2 and kw3 are allelic and kw is caused by a single recessive locus. KW gene specifically involves in controlling the identity of lateral petal. When KW mutated the lateral petal would be ventralized.