抗菌肽和几丁质酶基因提高烟草对黑胫病菌和赤星病菌的抗性研究

 通过农杆菌介导法将加信号肽修饰的人工合成杂合抗菌肽CEMA基因(SPCEMA),苜蓿防御素基因(AFP),苦瓜几丁质酶基因(CHI)以及SPCEMA-CHI、AFP-CHI、AFP-SPCEMA双价基因导入本明烟(Nicotiana benthamiana),并对转基因烟草T₀和T₁代进行了抗病性检测,比较了不同转基因植株的抗病效果。研究结果表明,转基因烟草对黑胫病菌(Phytophthora parasitica var.nicotianae)、赤星病菌(Alternaria alternata)的抗性均强于非转基因烟草,病情指数差异达极显著水平,其中转AFP-CHI双价基因烟草具有较强的抗性,与单价转基因烟草的抗性差异达显著水平。但各单价转基因以及双价转基因烟草之间对上述病菌并未表现出显著的抗病性差异。结果表明植物源的抗菌肽基因与几丁质酶基因在抗植物真菌病害中具有协同增效作用。

Overexpression of antimicrobial peptide genes and a chitinase gene in transgenic tobacco enhances resistance to Phytophthora parasitica var. nicotianae and Alternaria alternata

SPCEMA gene, a synthetic hybrid antimicrobial peptide(CEMA) with a signal peptide, an antifungal protein gene from alfalfa(AFP),a chitinase gene from balsam pear(CHI), and the gene combinations of SPCEMA-CHI, AFP-CHI and AFP-SPCEMA were introduced into Nicotiana benthamiana via Agrobacterium-mediated method. The resistance of T₀ and T₁ transgenic tobacco plants holding different gene cassettes to Phytophthora parasitica var. nicotianae and Alternaria alternata were detected and compared. The results showed that the transgenic tobacco exhibited higher resistance to the pathogens infected than that of the wildtype plants at the extreme-significance level. Additionally, the transgenic tobacco harboring AFP-CHI cassette showed the highest disease resistance among all the six types of transgenic plants and reached significant difference level over three single gene constructs. However, the difference of resistance was not at significant level in the single gene group, or in the double gene group. The results suggested that there was a synergetic effect in plant antimicrobial peptide gene and chitinase gene against pathogenic diseases.