过量表达LAR3和Bbchit1以提高毛白杨对叶枯病的抗性

Overexpression of LAR3 and Bbchit1 Genes in Transgenic Populus tomentosa Raising the resistance to Alternaria alternata

利用转基因技术将多种抗病基因共同转入毛白杨中以提高其抗性,从而获得毛白杨抗病新品种是目前解决杨树真菌病害的主要研究方向之一。本研究通过根癌农杆菌介导的二次遗传转化,将来源于球孢白僵菌几丁质酶基因Bbchit1转入过量表达无色花色素还原酶基因LAR3转基因毛白杨中,实时定量PCR显示Bbchit1与LAR3均能有效表达,离体抗病试验显示Bbchit1+LAR3共表达转基因毛白杨细胞粗提液对杨树叶枯病菌具有明显抑制作用,进一步将叶枯病菌接种在转基因和非转基因毛白杨叶片上培养30天,转基因植株的感病面积均低于非转基因植株且Bbchit1+LAR3共表达转基因株系抗病效果更明显。上述抗病试验结果表明:LAR3和Bbchit1在杨树中共表达可提高其对叶枯病的抗性。

Plant genetic engineering offers an alternative opportunity to enhance plant resistance to fungal pathogens. In this study, a chitinase gene （Bbchitl） from Beauveria bassiana was introduced into transgenic plants of Chinese white poplar （Populus tomentosa） which constitutively overexpresses LAR3 via Agrobacterium-mediated retransformation. The expression of Bbchitl and LAR3 was detected in transgenic plants by real time-PCR. In vivo assays demonstrated that the transgenic poplar plants displayed a significant reduction in their disease symptoms after infected with Alternaria alternata compared to control plants. These results suggest that constitutive expression of LAR3 and Bbchitl genes can be exploited to improve resistance to fungal pathogens in the poplar.