Conservation of Male Sterility 2 function during spore and pollen wall development supports an evolutionarily early recruitment of a core component in the sporopollenin biosynthetic pathway

Abstract

SummaryThe early evolution of plants required the acquisition of a number of key adaptations to overcome physiological difficulties associated with survival on land. One of these was a tough sporopollenin wall that enclosed reproductive propagules and provided protection from desiccation and UV-B radiation. All land plants possess such walled spores (or their derived homologue, pollen).We took a reverse genetics approach, consisting of knock-out and complementation experiments to test the functional conservation of the sporopollenin-associated gene MALE STERILTY 2 (which is essential for pollen wall development in Arabidopsis thaliana) in the bryophyte Physcomitrella patens.Knock-outs of a putative moss homologue of the A. thaliana MS2 gene, which is highly expressed in the moss sporophyte, led to spores with highly defective walls comparable to that observed in the A. thaliana ms2 mutant, and extremely compromised germination. Conversely, the moss MS2 gene could not rescue the A. thaliana ms2 phenotype.The results presented here suggest that a core component of the biochemical and developmental pathway required for angiosperm pollen wall development was recruited early in land plant evolution but the continued increase in pollen wall complexity observed in angiosperms has been accompanied by divergence in MS2 gene function.

OsACOS12, an orthologue of Arabidopsis acyl-CoA synthetase5, plays an important role in pollen exine formation and anther development in rice

“…For the ms2 mutant, PpMS2 driven by the MS2 promoter could not rescue its fertility. However, DPW driven by the MS2 promoter could rescue its fertility with normal pollen wall formation [32, 42]. These results suggested that DPW and MS2 have a very similar function, while PpMS2 and MS2 have evolutionary divergence.…”

Origin and function of stomata in the moss Physcomitrella patens

“…WT strain “Gransden 2004”, used for genome sequencing 32 , provided the genetic background for the generation of Δ PpSCRM1 mutants (“Gransden 2004”, Freiburg) and ‘Villersexel’ the genetic background for the generation of Δ PpSMF1 mutants (Sheffield), and “Gransden D12” was the background for production of the Δ PpSMF2 mutants. P. patens was grown axenically on BCDAT medium 33 supplemented with 1 mM calcium chloride and overlaid with cellophane discs (AA Packaging, UK), in 9 cm Petri dishes sealed with Micropore tape (3M) in Sanyo MLR incubators under continuous light (140 μmol m −2 s −1 ) at 25 °C 34 . P. patens (Freiburg) was grown in liquid or on solid (12 g/L purified agar (OXOID, Thermo Scientific, Waltham, MA, USA)) supplemented Knop medium 35,36 and cultivated at 23 °C under a 16-hour light and 8-hour dark cycle 37 .…”

iTRAQ-facilitated proteomic profiling of anthers from a photosensitive male sterile mutant and wild-type cotton (Gossypium hirsutum L.)

“…Moreover, Wallace et al reported that MS2 was an evolutionarily conserved core component in the sporopollenin biosynthetic pathway [64]. So, it raised our great interest in investigating the relationship between MS2 and male sterility in MT plants in our future research.…”