Fitness and mating consequences of variation in male allocation in a wind pollinated plant

In hermaphrodites, the allocation of resources to each sex function can influence fitness through reproductive success and mating success. In wind pollinated plants, sex allocation theory predicts that male fitness increases linearly with investment of resources into male function. However, there have been few empirical tests of this prediction. We experimentally manipulated allocation to male function in Ambrosia artemisiifolia (common ragweed) in a field experiment and measured mating success using genetic assays. We investigated the effects of various morphological traits and flowering phenology on male fitness, and on male and female mate diversity. Our results provide evidence for a linear relation between allocation to male function and fitness. We find earlier onset of male flowering time increases reproductive success, while later onset flowering time increases the probability of mating with diverse individuals. This research is among the first empirical studies testing the prediction of linear male fitness returns in wind pollinated plants. Our results provide insight into the large investment into male function by wind pollinated plants and temporal variation in sex allocation.

Epididymal sperm quality of Kacang goat preserved in low temperature for genetic material utilization in assisted reproductive technologies

Postmortem epidydimal preservation at low temperature (3-4°C), is a way to preserve and recover male genetic material. This effort aims for prolonging male function as sperm source, followed with its utilization in assisted reproductive technologies. This study aimed to observe the quality of sperm form cauda epididymis which preserved at low temperature for consecutive days. Sperm were retrieved from twelve cauda epididymis of Kacang Goat and its qualities namely motility, intact membrane, life/dead, and abnormality (all in %) were evaluated in every 2 days until 0% motility. Data were compared using analysis of variance at a = 0.05. Result shows significant (P<0.05) decrease in motility, intact membrane, and life/dead, but increase in abnormality during observation at day 0, day 2, day 4 and day 6, respectively. At the respective days, motility was 91.33±1.25%; 74.67±3.88%; 28.17±2.25% and 0.33±0.57%, intact membrane was 54.83±1.04%; 39±3.77%; 25.1±3.32% and 14.83±2.75%, life/dead was 55.17±4.01%; 36±3.5%; 24.3±3.25% and 12±2.78%, abnormality was 3.16±0.76%; 4.16±0.76%; 6.16±2.25% and 11±2.17%. According to the study, it is concluded that preserved sperm from cauda epididymis at low temperature shows decrease in quality and its utilization should rely on the quality status to select the most appropriate assisted reproductive technology.

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.

Geographic Patterns In Pollen Production In The Plant Ring Species Euphorbia tithymaloides In The Caribbean

Abstract—We examine investment in male function in the context of geography and floral morphology in the plant ring species Euphorbia tithymaloides, which colonized the Caribbean from Mexico/Guatemala along two fronts that roughly correspond to the Greater and the Lesser Antilles and that meet in the vicinity of the Anegada Passage. Our results on investment in pollen relative to ovule production are consistent with E. tithymaloides relying on pollinators for reproduction across its range in the Caribbean. We document a geographic pattern of reduction in anther number and pollen:ovule ratios in populations of E. tithymaloides towards the Anegada Passage, which is consistent with a possible geographic transition towards a mixed breeding system where selfing has increased importance in this area where its two expansion fronts meet. The reduction in pollen production is correlated with inflorescence morphology, which converges to relatively shorter cyathia towards the Anegada Passage along both fronts. We discuss alternative scenarios and potential drivers of the patterns we document.

Male evolution under relaxed selection: Evidence for degeneration in sperm produced by male snails from asexual lineages

How drastic changes in selective regimes affect trait evolution is an important open biological question. We take advantage of naturally occurring and repeated transitions from sexual to asexual reproduction in a New Zealand freshwater snail species to address how relaxed selection on male-specific traits influences sperm morphology. The occasional production of male offspring by the otherwise all-female asexual lineages allows a unique and powerful opportunity to assess the fate of sperm traits in a context where males are unnecessary. These comparisons revealed that the sperm produced by “asexual” males are markedly distinct from sexual counterparts. In particular, the asexual male sperm harbored markedly higher phenotypic variation and was much more likely to be morphologically abnormal. Together, these data suggest that transitions to asexual reproduction might be irreversible at least in part because male function is likely to be compromised. More broadly, our results are consistent with a scenario where relaxed selection translates into rapid trait degeneration.

A Silk-Expressed Pectin Methylesterase Confers Cross-Incompatibility Between Wild and Domesticated Strains of Zea mays

Despite being members of the same species, some strains of wild teosinte maintain themselves as a distinct breeding population by blocking fertilization by pollen from neighboring maize plants. These teosinte strains may be in the process of evolving into a separate species, since reproductive barriers that block gene flow are critical components in speciation. This trait is conferred by the Teosinte crossing barrier1-s (Tcb1-s) haplotype, making Tcb1 a speciation gene candidate. Tcb1-s contains a female gene that blocks non-self-type pollen and a male function that enables self-type pollen to overcome that block. The Tcb1-female gene encodes a Pectin Methylesterase, implying that modification of the pollen cell wall by the pistil is a key mechanism by which these teosinte females reject foreign (but closely related) pollen.One sentence summaryThe Tcb1-female gene encodes a Pectin Methylesterase that in teosinte silks prevents fertilization by maize pollen.