摘要
In peanuts, a mechanism of resistance to fungal infection is reported on the synthesis of stilbene phytoalexins, which are antibiotic, low molecular weight metabolites. The phytoalexin-associated response of different peanut varieties to the inoculation with A. flavus has not been investigated and might be useful for breed- ing resistant peanut cultivars. In this study, peanut varieties resistant or susceptible to aflatoxin accumulation caused by A. flavus were selected to compare the synthe- sis differences of the four main stilbenes （resveratrol, ε-viniferin, 6-viniferin and pterostilbene） and the activities of their resistant enzymes （PAL, POD, PPO）, and explore the relationship between stilbene synthesis and resistance to aflatoxin accu- mulation. The results indicated that the synthesis speed of stilbenes was related to the resistance to aflatoxin accumulation in peanuts seeds. The total content of the four stilbenes reached the highest value of 47.37 μg/g in the resistant cultivars （Qian huasheng 3） after inoculation by A. flavus （54 times of the control） on the 3nd day, while the total content of stilbenes in susceptible cultivars （Huayu 22） was 5.5 μg/g. The content of stilbenes and the activities of their resistant enzymes from the resistant cultivars were both higher than from the susceptible one. The four peanut varieties with relative higher stilbene contents and lower disease index and aflatoxin content were selected by using the stilbene content. Very significant negative corre- lation, with correlation coefficients （r） of -0.789, -0.851 and -0.850, was observed between the stilbene content with disease index, the content of aflatoxin B1 and the total content of aflatoxins, respectively. Therefore, the study suggested that the total content of stilbene compounds might serve as an important chemical index in peanut seeds after inoculation with A. flavus on the 3nd day, during screening and breeding of peanut varieties resistant to aflatoxin accumulation.
以花生种子为试材,采用孢子浓度为1×106(个/ml)的黄曲霉菌接种花生种子,对抗产毒和易产毒品种间4种主要芪化物(resveratrol,ε-viniferin,δ-viniferin,pterostilbene)合成变化,相关抗性酶活性(PAL、POD、PPO)进行了比较,探讨了不同品种间芪化物的合成与抗黄曲霉菌产毒之间的相关性。结果表明:花生种子芪化物的合成速度与抗产毒有关。在接种黄曲霉菌第3天时,抗产毒品种黔花生3号4种芪化物含量达到峰值,含量为47.37μg/g,为对照的54倍;易产毒品种花育22号芪化物含量仅5.5μg/g;抗产毒品种芪化物含量和相关抗性酶(PAL、POD、PPO)活性都高于易产毒品种;在16个考察的花生品种中,发现了4个芪化物含量较高,病情指数和黄曲霉毒素含量相对较低的花生品种;相关分析发现,不同花生品种芪化物含量与病情指数、黄曲霉毒素B_1和黄曲霉毒素总量呈极显著负相关,相关系数(r)分别为-0.789、-0.851、-0.850。因此,花生接种第3天时的芪化物含量可作为筛选和培育花生抗产毒品种的重要化学指标。
基金
Supported by Natural Science Foundation of Hainan Province(809034)
National Nonprofit Institute Research Grant of CATAS-TCGRI(1630032012025)~~
