Background

The brown planthopper (BPH) has become the most destructive and a serious threat to the rice production in Asia. Breeding the resistant varieties with improved host resistance is the most effective and ecosystem-friendly strategy of BPH biological management. As host resistance was always broken down by the presence of the upgrading BPH biotype, the more resistant varieties with novel resistance genes or pyramiding known identified BPH resistance genes would be needed urgently for higher resistant level and more durability of resistance.

Results

Here, we developed near isogenic lines of Bph9 (NIL-Bph9) by backcrossing elite cultivar 93–11 with Pokkali (harboring Bph9) using marker-assisted selection (MAS). Subsequently, we pyramided Bph6 and Bph9 in 93–11 genetic background through MAS. The resulting Bph6 and Bph9 pyramided line LuoYang69 had stronger antixenotic and antibiosis effects on BPH and exhibited significantly enhanced resistance to BPH than near isogenic lines NIL-Bph6 and NIL-Bph9. LuoYang69 derived hybrids, harboring heterozygous Bph6 and Bph9 genes, also conferred high level of resistance to BPH. Furthermore, LuoYang69 did not affect the elite agronomic traits and rice grain quality of 93–11. The current study also developed functional markers for Bph9. Using functional dominant marker, we screened and evaluated worldwide accessions of rice germplasm. Of the 673 varieties tested, 8 cultivars were identified to harbor functional Bph9 gene.

Conclusion

The development of Bph6 and Bph9 pyramided line LuoYang69 provides valuable resource to develop hybrid rice with highly and durable BPH resistance. The development of functional markers will promote MAS of Bph9. The identified Bph9 containing cultivars can be used as new sources for BPH resistance breeding programs.

中文翻译：

---

标记物协助将Bph6和Bph9金字塔化成精英恢复系93-11，并开发了Bph9的功能性标记物。

背景

褐飞虱（BPH）已成为亚洲稻米生产中最具破坏力的严重威胁。选育具有更高抗宿主性的抗性品种是BPH生物管理最有效，最有利于生态系统的策略。由于宿主抗性总是被升级的BPH生物型破坏，因此迫切需要具有新抗性基因或具有金字塔结构的已知BPH抗性基因的更抗性品种，以获得更高的抗性水平和更持久的抗性。

结果

在这里，我们通过标记辅助选择（MAS）使优良品种93-11与Pokkali（携带Bph9）回交，从而在Bph9（NIL- Bph9）的等基因系附近发育。随后，我们通过MAS在93-11遗传背景中将Bph6和Bph9金字塔化。与近等基因系NIL- Bph6和NIL- Bph9相比，所产生的Bph6和Bph9金字塔系LuoYang69对BPH具有较强的抗排异作用和抗菌作用，并表现出对BPH的抗性明显增强。LuoYang69衍生的杂种，具有杂合Bph6和Bph9基因，也赋予了对BPH的高水平抗性。此外，LuoYang69对93-11的优良农艺性状和稻米品质没有影响。当前的研究还开发了Bph9的功能标记。我们使用功能优势标记，筛选和评估了世界水稻种质的种质。在测试的673个品种中，鉴定出8个具有功能性Bph9基因的品种。

结论

发展Bph6和Bph9的节节线LuoYang69提供了宝贵的资源，开发具有高耐用抗褐飞虱杂交水稻。功能标记的发展将促进Bph9的MAS 。鉴定出的含有Bph9的品种可以用作BPH抗性育种计划的新来源。