Effects of interaction between pollen coat eluates and pistil at the molecular level in self-compatible and self-incompatible plants ofLolium multiflorum Lam.

Abstract

Two-dimensional electrophoresis (2-DE) of soluble proteins and enzymes was performed and specific activities of 5 enzymes (esterase, pectinesterase, acid phosphatase, protease and diaphorase) were determined in stigmas of Lolium multiflorum (Italian ryegrass) treated with self or foreign pollen coat eluates (pc). Also, a low-molecular-weight fraction of the treated self-compatible (SC) and self-incompatible (SI) stigmas was analyzed by high-pressure liquid chromatography (HPLC). The treatment of stigmas with foreign pollen induced the loss of 42% of the control sample proteins in SC plants but only of 5.5% in SI plants. In contrast, the treatment of stigmas with foreign pollen induced the loss of 15% proteins in SC plants and of 29% in SI plants. Specific activities of esterase, pectinesterase and diaphorase were higher in SC than in SI stigmas. The 2-DE enzyme patterns indicated qualitative relationships between the presence of some isoforms of acid phosphatase or protease and the treatment with self or foreign pc in SC and SI stigmas. No changes were observed in HPLC profiles of the low-molecular-weight fraction from SC and SI stigmas treated or not with pc. The presented results revealed different reactions of SC and SI stigmas to the treatment with self or foreign pc. Further investigations may explain if any of the observed reactions represent specific reorientations in the style, facilitating cross- or self-pollination.

The Pollen Coat Proteome: At the Cutting Edge of Plant Reproduction

“…As with maize, several β-expansins and expansin-like proteins, a putative tapetum-specific 1,4-β-xylanase of 30 kDa and a ~70-kDa β-glucanase constitute, in that order, the bulk of the rice pollen coat proteome. The pollen coat proteins extracted from Secale cereale , Festuca pratensis and Lilium multiflorum self-sterile and self-fertile plants [81,82], as well as from Aegilops kotschyi × S. cereale amphiploid plants [83], were also profiled by 2-DE, although these studies lack protein identification data. The proteomic analysis of rapidly released proteins from maize [44], rice [26] and triticale [38] pollen upon hydration led to the identification of novel putative candidates of the pollen coat proteome.…”

Progress towards elucidating the mechanisms of self-incompatibility in the grasses: further insights from studies in Lolium

“…The grass SI reaction has also been preliminarily investigated at the level of changed protein accumulation and enzymatic activity in isolated styles treated with pollen coat eluates in Lolium multiflorum (Kalinowski et al, 2006). The protein profile in two-dimensional PAGE analysis changed considerably between self-compatible and self-incompatible combinations.…”