利用半胱胺酸蛋白酶抑制因子及幾丁質酶之雙基因轉殖發展抗根瘤線蟲的耐熱番茄品系

Abstract

根瘤線蟲 (root-knot nematode, RKN) 為植物內寄生性線蟲，可以危害多種經濟作物，而造成作物產量及經濟上的損失。對根瘤線蟲的防治策略以化學藥劑的施用為主，而化學藥劑的使用會危害人類及汙染環境，因此我們希望以基因轉殖作物替代化學藥劑防治根瘤線蟲。本實驗室利用人工合成的 pMSPOA 表現來自芋頭的半胱胺酸蛋白酶抑制因子基因 (cysteine protease inhibitor, CeCPI) 及來自 Paecilomyces javanica 的幾丁質酶基因 (chitinase-1, PjCHI-1) 於耐熱番茄 (Solanum lycopersicum Mill.) 品系CLN2468D 中，測試此寄主對南方根瘤線蟲 (Meloidogyne incognita) 抗性反應。非轉殖株與轉殖株 pMSPOA::CeCPI- pMSPOA::PjCHI-1在感染根瘤線蟲的六週後，測試它們的抗性能力。轉殖株大量表現 CeCPI 於植物體內，可以抑制根瘤的形成，也減少母蟲所占族群百分比而降低線蟲子代數量;另外，具有高量表達 PjCHI-1 的轉殖株，可以減少卵殼的幾丁質含量，降低卵及卵塊數量及阻礙蟲卵胚胎正常的發育，此結果表示轉殖 pMSPOA::CeCPI- pMSPOA::PjCHI-1 於耐熱番茄中，可以大量表達此兩基因於植物體內，因此有效的抑制線蟲的繁殖力及減少線蟲的後代。

Root-knot nematodes are sendentary parasitic nematode, they attack multiple economic crops and cause productivity and economic losses. The strategies of nematode control are culture management, resistant cultivar and nematocide. Although useful nematocide is used to reduce nematode population, it causes the enormous harm to human and environment. Through, our goal is to engineer the nematode-resistant plant to replace nematocide. We construct the Colocasia esculenta cysteine protease inhibitor (CeCPI) and Paecilomyces javanicus chitinase-1(PjCHI-1) driven by a synthetic promoter, pMSPOA . 6 weeks afeter root-knot nematode infection, we calculate the root galls and egg mass, and we find that the number of root galls and egg mass are reduced. In the previous study, we know that CeCPI can affect the nematode digestion and PjCHI-1 can destroy the egg shell. The transgenic plants showed prominently the reduction of saccate, decline of enlarged saccate female percentage, lack of chitin content, decrease of eggs per egg mass and retardation of embryogenesis. In conclusion, the transgenic plants which are overexpressed PjCHI nad CeCPI can effectively control the propagation Meloidogyne incognita and to decline nematode progeny.