SWATH-MS based quantitive proteomics reveal regulatory metabolism and networks of androdioecy breeding system in Osmanthus fragrans

Background The fragrant flower plant Osmanthus fragrans has an extremely rare androdioecious breeding system displaying the occurrence of males and hermaphrodites in a single population, which occupies a crucial intermediate stage in the evolutionary transition between hermaphroditism and dioecy. However, the molecular mechanism of androdioecy plant is very limited and still largely unknown. Results Here, we used SWATH-MS-based quantitative approach to study the proteome changes between male and hermaphroditic O. fragrans pistils. A total of 428 proteins of diverse functions were determined to show significant abundance changes including 210 up-regulated and 218 down-regulated proteins in male compared to hermaphroditic pistils. Functional categorization revealed that the differentially expressed proteins (DEPs) primarily distributed in the carbohydrate metabolism, secondary metabolism as well as signaling cascades. Further experimental analysis showed the substantial carbohydrates accumulation associated with promoted net photosynthetic rate and water use efficiency were observed in purplish red pedicel of hermaphroditic flower compared with green pedicel of male flower, implicating glucose metabolism serves as nutritional modulator for the differentiation of male and hermaphroditic flower. Meanwhile, the entire upregulation of secondary metabolism including flavonoids, isoprenoids and lignins seem to protect and maintain the male function in male flowers, well explaining important feature of androdioecy that aborted pistil of a male flower still has a male function. Furthermore, nine selected DEPs were validated via gene expression analysis, suggesting an extra layer of post-transcriptional regulation occurs during O. fragrans floral development. Conclusion Taken together, our findings represent the first SWATH-MS-based proteomic report in androdioecy plant O. fragrans, which reveal carbohydrate metabolism, secondary metabolism and post-transcriptional regulation contributing to the androdioecy breeding system and ultimately extend our understanding on genetic basis as well as the industrialization development of O. fragrans.

Reproductive biology of Stomatium bolusiae (Aizoaceae: Ruschioideae)

Flowers of Stomatium bolusiae are self-incompatible. The species exhibits crepuscular and nocturnal anthesis, exploiting two different pollination mechanisms. The structure of the hermaphroditic flower appears not to favour cross-pollination. The stigmata are never exposed to pollinating agents, which gain access to the floral rewards by forcing their way between the anthers. Clogging of the stigmatic surfaces by self-pollen is common. Nocturnal anthesis, concomitant with the nocturnal release of attractants and the offering of rewards, indicates that this species is primarily phalaenophilous and secondarily melittophilous, exhibiting a bimodal pollination system.

Male and hermaphrodite flowers in the alpine lily Lloydia serotina

In perennial species that produce only one flower per individual each year, androdiœcy (coexistence of genetic male and hermaphrodite individuals) may be difficult to distinguish from andromonœcy (male and hermaphrodite flowers on the same plant). We show that the alpine lily, Lloydia serotina Rchb., produces functionally male and hermaphroditic flowers. Mean male frequency in 11 populations in the French Alps was 48.5%, ranging from 15.5 to 67.5%. Male flowers do not produce more pollen nor sire more seeds per flower in controlled pollinations than hermaphrodite flowers. Male floral scapes were consistently shorter than those of hermaphrodites. Out of several thousand observed floral scapes, four had two flowers, all with a terminal hermaphroditic flower and an axillary male one. Among 107 bulbs transplanted in pots in 1996, eighteen expressed a different sexual phenotype in 1999 or 2000, and one hermaphrodite produced two flowers of different sexes in 2000. Together, these results suggest that L. serotina is andromonœcious throughout its lifetime.Key words: Lloydia serotina, andromonœcy, male reproductive success, Liliaceae.