PDF(Pubmed)
Abstract：
CONCLUSIONS: Australian native species of sorghum contain negligible amounts of dhurrin in their leaves and the cyanogenesis process is regulated differently under water-stress in comparison to domesticated sorghum species. Cyanogenesis in forage sorghum is a major concern in agriculture as the leaves of domesticated sorghum are potentially toxic to livestock, especially at times of drought which induces increased production of the cyanogenic glucoside dhurrin. The wild sorghum species endemic to Australia have a negligible content of dhurrin in the above ground tissues and thus represent a potential resource for key agricultural traits like low toxicity. In this study we investigated the differential expression of cyanogenesis related genes in the leaf tissue of the domesticated species Sorghum bicolor and the Australian native wild species Sorghum macrospermum grown in glasshouse-controlled water-stress conditions using RNA-Seq analysis to analyse gene expression. The study identified genes, including those in the cyanogenesis pathway, that were differentially regulated in response to water-stress in domesticated and wild sorghum. In the domesticated sorghum, dhurrin content was significantly higher compared to that in the wild sorghum and increased with stress and decreased with age whereas in wild sorghum the dhurrin content remained negligible. The key genes in dhurrin biosynthesis, CYP79A1, CYP71E1 and UGT85B1, were shown to be highly expressed in S. bicolor. DHR and HNL encoding the dhurrinase and α-hydroxynitrilase catalysing bio-activation of dhurrin were also highly expressed in S. bicolor. Analysis of the differences in expression of cyanogenesis related genes between domesticated and wild sorghum species may allow the use of these genetic resources to produce more acyanogenic varieties in the future.
摘要：
结论：澳大利亚本地高粱物种的叶片中含有可忽略不计的dhurrin，与驯化的高粱物种相比，在水分胁迫下，产卵过程的调节方式不同。饲草高粱中的氰化发生是农业中的主要问题，因为驯化高粱的叶子对牲畜有潜在的毒性，尤其是在干旱时期，干旱会导致生氰葡糖苷dhurrin的产量增加。澳大利亚特有的野生高粱物种在地上组织中的dhurrin含量可忽略不计，因此代表了低毒性等关键农业性状的潜在资源。在这项研究中，我们使用RNA-Seq分析分析基因表达，研究了在温室控制的水分胁迫条件下生长的驯化物种双色高粱和澳大利亚本土野生高粱的叶片组织中与发蓝相关的基因的差异表达。这项研究确定了基因，包括产卵途径中的那些，在驯化和野生高粱中对水分胁迫的反应不同。在驯化的高粱中，与野生高粱相比，dhurrin含量明显更高，并且随着胁迫而增加，随着年龄的增长而减少，而在野生高粱中，dhurrin含量仍然可以忽略不计。dhurrin生物合成的关键基因，CYP79A1、CYP71E1和UGT85B1在双色链球菌中高表达。编码dhurrinase和α-羟基腈水解酶催化dhurrin生物活化的DHR和HNL也在双色链球菌中高度表达。分析驯化和野生高粱物种之间的产卵相关基因表达差异，可能会使将来利用这些遗传资源产生更多的产卵变种。
