A novel barley scald resistance gene: genetic mapping of the Rrs15 scald resistance gene derived from wild barley, Hordeum vulgare ssp. spontaneum

Most genes for resistance to barley leaf scald map either to the Rrs1 locus on the long arm of chromosome 3H, or the Rrs2 locus on the short arm of chromosome 7H. Other loci containing scald resistance genes have previously been identified using lines derived from wild barley, Hordeum vulgare ssp. spontaneum. A single dominant gene conditioning resistance to scald was identified in a third backcross (BC3F3) line derived from an Israeli accession of wild barley. The resistance gene is linked to three microsatellite markers that map to the long arm of chromosome 7H; the closest of these loci, HVM49, maps 11.5 cM from the resistance gene. As no other scald resistance genes have been mapped to this chromosome arm, it is considered to be a novel scald resistance locus. As the Acp2 isozyme locus is linked to this scald resistance locus, at 17.7 cM, Acp2 is assigned to chromosome 7H. Molecular markers linked to the novel scald resistance gene, designated Rrs15, can be used in breeding for scald resistance.     

鹤顶兰胚珠发育过程及受精前后同工酶的变化

 通过光学显微镜观察发现：鹤顶兰[Phaius tankervilliae (Aiton) Bl.]授粉10 d出现指状突起,20 d形成胚珠原基,24 d大孢子母细胞发生,30 d功能大孢子形成,41 d发育为成熟的八核胚囊,而后完成双受精发育成早期球形胚。用聚丙烯酰胺凝胶电泳的方法研究鹤顶兰从指状突起出现到早期球形胚形成的全过程中酯酶（Est）、酸性磷酸酶（Acp）的变化发现：这一过程中酯酶（Est）表达有7个同工酶位点,酸性磷酸酶（Acp）有5个同工酶位点,两者均在八核胚囊时期变化最显著。Est-7和Acp-4在整个发育过程中都有表达;在八核胚囊时期特异表达的位点有Est-4和Acp-3;而Acp-2只在这一时期不表达。Est-1在八核胚囊时期和大孢子母细胞减数分裂I中期表达。授粉后Est和Acp的酶位点变化说明与胚珠发育相关的一系列基因表达有时序性,位点Est-4、Acp-2和Acp-3是否直接参与了八核胚囊发育的控制,有待于进一步的研究。