In order to clarify the difference of jasmonic acid (JA) synthesis and signal pathway genes expression in pepper before and after aphid feeding, the molecular mechanism of JA pathway-mediated resistance to aphid in pepper was preliminarily clarified based on the effects of aphid densities and infestation time. The aphid-resistant pepper variety ZDC and aphid-susceptible pepper variety DYJJ were used as the materials. The expression changes of JA synthesis pathway genes (LOX2, AOS, AOC and OPR3) and signal pathway genes (COI1 and JAR1) related to plant defense were analyzed by real-time quantitative PCR after aphid density (20, 30, 40, 50 and 60 aphids/leaf) and feeding time (6, 12, 24, 48 and 72 h). The results showed that under different aphid population densities and infestation time, the expression levels of the four genes in JA synthesis pathway in ZDC were generally significantly higher than those in DYJJ, while the expression levels of the two genes in signal pathway were generally significantly lower than those in DYJJ. Under the condition of low aphid damage level, there were significant differences in the expression levels between resistant and susceptible pepper varieties, and the peak and trough time of some gene expression were basically the same under the same aphid population density. Under high level of damage, the difference between resistant and susceptible pepper varieties decreased significantly. The above results showed that JA synthesis and signaling pathways AOS, AOC and JAR1 genes might have the potential to be used as molecular indicators for the identification and evaluation of aphid resistance in pepper, which could provide a theoretical basis for the evaluation and innovative utilization of aphid-resistant germplasm resources in pepper in the future.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |