Identification and characterization of two Bamboo (Phyllostachys praecox) AP1/SQUA-like MADS-box genes during floral transition

Abstract

Bamboo (Bambusoideae) is by far the largest member of the grass family Poaceae, which is vital to the economy of many countries in the tropics and subtropics. However, the mechanism of flowering of bamboo (Phyllostachys praecox) is still unknown. In this study, we isolated two novel genes from P. praecox and evaluated their functional characteristics. The sequence and phylogenetic analysis indicated that these two genes, named PpMADS1 and PpMADS2, belong to FUL3 and FUL1 clade of Poaceae AP1/SQUA-like genes, respectively. The PpMADS2 possesses a truncated C terminus lacking the highly conserved paleoAP1 motif. It was further confirmed that the truncated C-terminal region was produced by natural sequence deletion in exons, but not by alternative splicing. Ectopic expression of PpMADS1 and PpMADS2 significantly promoted early flowering through upregulation of AP1 in Arabidopsis. Yeast two-hybrid experiments demonstrated that AP1 protein can interact with PpMADS1 but not PpMADS2, suggesting that these two genes may act differently in signaling early flowering of bamboo plants. RT-qPCR and in situ hybridization analysis revealed distinct expression patterns of these two genes in vegetative and reproductive tissues of bamboo. Taken together, our results suggest that both PpMADS1 and PpMADS2 are involved in floral transition, and PpMADS2 might play more important roles than PpMADS1 in floral development of Phyllostachys praecox.

An APETALA1-like gene of soybean regulates flowering time and specifies floral organs

“…Concomitantly, the transgenic lines displayed a dwarf phenotype that is the result of transition to reproductive growth early in development. This finding was consistent with ectopic overexpression of AP1-like genes in other species (Berbel et al, 2001;Lin et al, 2009), which indicates AP1-like genes are functionally conserved as a floral promoter in plants.…”

Ectopic expression of the BoTFL1-like gene of Bambusa oldhamii delays blossoming in Arabidopsis thaliana and rescues the tfl1 mutant phenotype

“…It is well-known for its edible shoots and green timber, and is one of the most economically important forest resources in tropical and subtropical countries (Hsu et al, 2000;Lin et al, 2009). The majority of bamboos do not flower until they are approximately 30-to 60-yearsold.…”

“…Bamboo flowering is unpredictable, gregarious, and the plants usually die after flowering. This not only reduces local income, but also causes ecological and environmental problems (Daniel and Janzen, 1976;Lin et al, 2009). Therefore, there are compelling reasons to study the genetics of the flowering mechanism in bamboos.…”

“…Thus, DIMADS1-18 full-length cDNA sequences were isolated from the panicles of Dendrocalamus latiflorus and it was found that overexpression of DlMADS8 or DlMADS18 in Arabidopsis causes leaf curl and an early flowering phenotype (Tian et al, 2005(Tian et al, , 2006. Two AP1/SQUA-like MADS-box genes, PpMADS1 and PpMADS2 were isolated from Phyllostachys praecox during floral transition; in Arabidopsis, overexpression of these genes significantly promotes early flowering through upregulation of AP1 (Lin et al, 2009). Two cDNA libraries have been established from flower buds and vegetative shoots of B. oldhamii.…”

Genome-wide identification of MADS-box family genes in moso bamboo (Phyllostachys edulis) and a functional analysis of PeMADS5 in flowering

“…Lin identified two AP/SQUA-like MADS-box genes from Phyllostachys praecox , PpMADS1 (FUL3 subfamily) and PpMADS2 (FUL1 subfamily) [30]. Both genes play vital roles in the floral transition of bamboo.…”