Identification, characterization and functional analysis of AGAMOUS subfamily genes associated with floral organs and seed development in Marigold (Tagetes erecta).

BACKGROUND: AGAMOUS (AG) subfamily genes regulate the floral organs initiation and development, fruit and seed development. At present, there has been insufficient study of the function of AG subfamily genes in Asteraceae. Marigold (Tagetes erecta) belongs to Asteraceae family whose unique inflorescence structure makes it an important research target for understanding floral organ development in plants. RESULTS: Four AG subfamily genes of marigold were isolated and phylogenetically grouped into class C (TeAG1 and TeAG2) and class D (TeAGL11-1 and TeAGL11-2) genes. Expression profile analysis demonstrated that these four genes were highly expressed in reproductive organs of marigold. Subcellular localization analysis suggested that all these four proteins were located in the nucleus. Protein-protein interactions analysis indicated that class C proteins had a wider interaction manner than class D proteins. Function analysis of ectopic expression in Arabidopsis thaliana revealed that TeAG1 displayed a C function specifying the stamen identity and carpel identity, and that TeAGL11-1 exhibited a D function regulating seed development and petal development. In addition, overexpression of both TeAG1 and TeAGL11-1 leaded to curling rosette leaf and early flowering in Arabidopsis thaliana. CONCLUSIONS: This study provides an insight into molecular mechanism of AG subfamily genes in Asteraceae species and technical support for improvement of several floral traits.

[Effects of seed soaking with biogas slurry on seed germination and seedling growth of Tagetes erecta].

OBJECTIVE: The experiment was conducted to study the effect of soaking seeds with biogas slurry on seed germination and growth of Tagetes erecta so that we can provide theory base for cultivation management of T. ercta. METHOD: In order to find the best combine of biogas slurry concentration (25%, 50%, 75%, 100%) and soaking time (2, 3, 4, 5 h), completely randomized design was selected, germination percentage, seedling height, root length, root activity, content of chlorophyll (a, b) and MDA were analyzed and principle component analysis was adopted. RESULT: Both soaking for 5 h in 25% biogas slurry and soaking for 4 h in 50% biogas slurry had the highest germination percentage (81.3%). Soaking for 5 h in 50% biogas slurry had the longest root, and soaking for 4 h in 50% biogas slurry had the highest root activity. They were significant higher than other 19 treatments. Soaking for 5 h in 50% biogas slurry had the highest content of chlorophyll a, chlorophyll b, chlorophyll (a + b) and ratio of chlorophyll a/ chlorophyll b. It was significant higher in these index, except b, than other 19 treatment. Soaking for 5 h in 25% biogas slurry had the lowest MDA content (0.0280 micromol x L(-1)), then was Soaking for 4 h in 50% biogas slurry (0.0286 micromol x L(-1) in MDA content). CONCLUSION: Appropriate biogas slurry concentration combined with seed soaking time can improve the germination and growth of T. erecta. As a whole, soaking for 5 h in 50% biogas slurry had the best effects on germination and growth in seedling stage for T. erecta.