ONLY SPECIFIC TOBACCO (NICOTIANA-TABACUM) CHITINASES AND BETA-1,3-GLUCANASES EXHIBIT ANTIFUNGAL ACTIVITY
ONLY SPECIFIC TOBACCO (NICOTIANA-TABACUM) CHITINASES AND BETA-1,3-GLUCANASES EXHIBIT ANTIFUNGAL ACTIVITY
复制标题
DOI：
10.1104/pp.101.3.857
复制
发表时间：
1993-03-01
期刊：
影响因子：
7.4
通讯作者：
CORNELISSEN, BJC
中科院分区：
文献类型：
--
作者：
SELABUURLAGE, MB;PONSTEIN, AS;CORNELISSEN, BJC
对烟草（Nicotiana tabacum cv Samsun NN）不同几丁质酶和-1,3-葡聚糖酶的抑菌活性进行了测定。I类、液泡几丁质酶和β -1,3-葡聚糖酶同工型对茄枯菌萌发最具活性，可导致菌丝顶端裂解和生长抑制。此外，我们还观察到I类几丁质酶和-1,3-葡聚糖酶具有协同作用。这两种水解酶的II类同工型没有抗真菌活性。然而，II类几丁质酶在与大量的I类β -1,3-葡聚糖酶结合时显示出有限的生长抑制活性。II类β -1,3-葡聚糖酶在任何组合下均无抑制活性。在产生I类几丁质酶或I类β -1,3-葡聚糖酶或两者的修饰形式的转基因烟草植物中，这些蛋白质是在细胞外靶向的。这两种修饰蛋白都缺乏作为液泡靶向信号的c端前肽。细胞外靶向对几丁质酶和β -1,3-葡聚糖酶的特异性活性没有影响。此外，从表达这两种酶的转基因植物叶片中提取的细胞外洗涤液（EF）在体外对茄茄病菌的抗真菌活性与纯化的液泡I类蛋白相当。混合这些植物的EF组分显示出对茄枯病菌的协同抑制活性；混合组分表现出与表达两种分泌酶的植物EF相似的抑制活性。
Different isoforms of chitinases and beta-1,3-glucanases of tobacco (Nicotiana tabacum cv Samsun NN) were tested for their antifungal activities. The class I, vacuolar chitinase and beta-1,3-glucanase isoforms were the most active against Fusarium solani germlings, resulting in lysis of the hyphal tips and in growth inhibition. In addition, we observed that the class I chitinase and beta-1,3-glucanase acted synergistically. The class II isoforms of the two hydrolases exhibited no antifungal activity. However, the class II chitinases showed limited growth inhibitory activity in combination with higher amounts of class I beta-1,3-glucanase. The class II beta-1,3-glucanases showed no inhibitory activity in any combination. In transgenic tobacco plants producing modified forms of either a class I chitinase or a class I beta-1,3-glucanase, or both, these proteins were targeted extracellularly. Both modified proteins lack their C-terminal propeptide, which functions as a vacuolar targeting signal. Extracellular targeting had no effect on the specific activities of the chitinase and beta-1,3-glucanase enzymes. Furthermore, the extracellular washing fluid (EF) from leaves of transgenic plants expressing either of the secreted class I enzymes exhibited antifungal activity on F. solani germlings in vitro comparable to that of the purified vacuolar class I proteins. Mixing EF fractions from these plants revealed synergism in inhibitory activity against F. solani; the mixed fractions exhibited inhibitory activity similar to that of EF from plants expressing both secreted enzymes.