Twenty-six orthologs of the rice blast resistance gene Pid3 from cultivated varieties and wild rice accessions distributed in different areas were cloned by allele mining. Sequence analysis showed that while each of the orthologous genes from indica varieties and most wild accessions encodes a complete NBS-LRR protein, each of the proteins encoded by those from japonica varieties and few wild rice accessions presents a premature termination. Eleven of the 26 orthologs were selected for blast resistance testing by transforming into the blast susceptible rice variety TP309, respectively. Inoculation of 23 M. oryzae strains collected from diverse regions of China to the respective transgenic plants revealed that 6 Pid3 orthologs showed susceptible to all the tested strains, while the other 5 orthologs showed differential resistance spectra in a gradually spectrum-widen order as Pid3-W3, Pid3-W4, Pid3-I3, Pid3-W5 and Pid3-I1. Amino acid sequences alignment of these orthologs indicated that the sequence diversities between the blast resistance orthologs were mostly located in the LRR domain such as the substitutions of Q694H,D856H,Q896R,D899E etc. However, the differences between the resistance orthologs and the susceptible ones were mostly located in the NBS domain. The present experiments provide an example of that the ortholog evaluation of plant R genes could be an efficient way to expand the rice blast resistance and some other plant disease resistance as well for breeding.

Sex-specific responses to mycorrhiza have been reported in dioecious plant species, but little attention has been paid to the influence of arbuscular mycorrhizal (AM) fungi on competitive ability under intersexual competition. To further address whether this competition is affected by an additional AM fungi supply, Populus cathayana saplings were chosen and subjected to two mycorrhizal treatments [inoculated and non-inoculated (control) with an additional AM fungi Funneliformis mosseae] while growing with the opposite sex for 3 months. Compared with the control, the additional AM fungi inoculation induced P. cathayana saplings to exhibit significant sexual differences in root structure and nutrient uptake (e.g., cortical layer, cross-section area, radius of root tips, and N, K, and Mg content), and enlarged sexual differences in morphology and biomass accumulation (e.g., leaf number increment, shoot height increment, total leaf area, total specific root length, stem dry mass, leaf dry mass, and total dry mass). Meanwhile, inoculated females presented higher values in most of these traits mentioned above than males under intersexual competition. Therefore, we conclude that the intersexual competition can be increased by an additional AM fungi supply, with females gaining more symbiosis-mediated benefits than males.

Females and males of dioecious plants have evolved sex-specific characteristics in terms of their morphological and physiological properties. However, the differentiation of phyllosphere microbiota in dioecious plants remains largely unexplored. Here, the diversity and composition of female and male Populus cathayana phyllosphere bacterial and fungal communities were investigated using 16S rRNA/ITS1 gene–based MiSeq sequencing. The divergences of bacterial and fungal community compositions occurred between females and males. Both females and males had their unique phyllosphere bacterial and fungal microbiota, such as bacterial Gemmata spp. (5.41%) and fungal Pringsheimia spp. (0.03%) in females and bacterial Chitinophaga spp. (0.009%) and fungal Phaeococcomyces spp. (0.02%) in males. Significant differences in the relative abundance of phyla Proteobacteria and Planctomycetes bacteria and phyla Ascomycota and Basidiomycota fungi (P < 0.05) were also found between females and males. Some bacterial species of genera Spirosoma and Amnibacterium and fungal genera Venturia, Suillus, and Elmerina spp. were significantly enriched in males (P < 0.05). In contrast, levels of fungal genera Phoma and Aureobasidium spp. were significantly higher in females than in males (P < 0.05). The mineral, inorganic, and organic nutrients content contributed differently to the divergence of female and male phyllosphere microbial communities, with 87.08 and 45.17% of the variations being explained for bacterial and fungal communities, respectively. These results highlight the sexual discrimination of phyllosphere microbes on the dioecious plants and provide hints on the potential host-associated species in phyllosphere environments. [ ] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

Relationships between sex‐specific floral traits and endogenous phytohormones associated with altitude are unknown particularly in dioecious trees. We thus examined the relationships between floral morphology or biomass and phytohormones in male and female flowers of dioecious Populus cathayana populations along an altitudinal gradient (1,500, 1,600, and 1,700 m above sea level) in the Xiaowutai Nature Reserve in northern China. The female and male flowers had the most stigma and pollen at 1,700 m, the largest ovaries and least pollen at 1,500 m, and the smallest ovaries and greater numbers of anthers at 1,600 m altitude. The single‐flower biomass was significantly greater in males than in females at 1,600 or 1,700 m, but the opposite was true at 1,500 m altitude. The biomass percentages were significantly higher in anthers than in stigmas at each altitude, while significantly greater gibberellin A3 (GA₃), zeatin riboside (ZR), indoleacetic acid (IAA), and abscisic acid (ABA) concentrations were found in female than in male flowers. Moreover, most flower morphological traits positively correlated with IAA in females but not in males. The biomass of a single flower was significantly positively correlated with ABA or IAA in males but negatively with ZR in females and was not correlated with GA₃ in both females and males. Our results demonstrate a distinct sexual adaptation between male and female flowers and that phytohormones are closely related to the size, shape, and biomass allocation in the pollination or fertilization organs of dioecious plants, although with variations in altitude.