Turgor regulation defect 1 proteins play a conserved role in pollen tube reproductive innovation of the angiosperms

Abstract

SUMMARY Sexual reproduction in angiosperms is siphonogamous, and the interaction between pollen tube and pistil is critical for successful fertilization. Our previous study demonstrated that mutation of the Arabidopsis turgor regulation defect 1 (TOD1) gene leads to reduced male fertility, a result of retarded pollen tube growth in the pistil. TOD1 encodes a Golgi‐localized alkaline ceramidase, a key enzyme for the production of sphingosine‐1‐phosphate (S1P), which is involved in the regulation of turgor pressure in plant cells. However, whether TOD1s play a conserved role in the innovation of siphonogamy is largely unknown. In this study, we provide evidence that OsTOD1, which is similar to AtTOD1, is also preferentially expressed in rice pollen grains and pollen tubes. OsTOD1 knockout results in reduced pollen tube growth potential in rice pistil. Both the OsTOD1 genomic sequence with its own promoter and the coding sequence under the AtTOD1 promoter can partially rescue the attod1 mutant phenotype. Furthermore, TOD1s from other angiosperm species can partially rescue the attod1 mutant phenotype, while TOD1s from gymnosperm species are not able to complement the attod1 mutant phenotype. Our data suggest that TOD1 acts conservatively in angiosperms, and this opens up an opportunity to dissect the role of sphingolipids in pollen tube growth in angiosperms.

Molecular regulation of tomato male reproductive development

“…Flowering plants are among the most successful living organisms at least partly because of their morphological diversity and ability to grow in various ecological niches, which is primarily because of reproductive innovations (Chen et al 2019 ; Ge et al 2010 ). Reproductive development is crucial for the maintenance of genetic diversity and involves complex processes during diploid and haploid phases, including male and female organogenesis, meiosis, gametogenesis, pollination, and fertilization (Ke et al 2021 ; Liu et al 2021 ; Ma 2005 ). Fruits and seeds are two major components of human diets; their production depends on reproductive development-related activities (Gao et al 2015 ; Li et al 2018b ).…”