Detecting Host-Plant Volatiles with Odorant Receptors from Grapholita molesta (Busck) (Lepidoptera: Tortricidae)

Abstract

Grapholita molesta is a global pest of stone and pome fruits. The sensitive olfactory system plays a crucial role in regulating key behavioral activities of insects and G. molesta relies heavily on general odorant receptors (ORs) to detect host-plant volatiles. In this study, three general OR genes from G. molesta (GmolOR12, GmolOR20, and GmolOR21) were identified. Quantitative polymerase chain reaction revealed that GmolORs expression was considerably higher in adults and adult antennae than in any other life stages and body parts, respectively. Moreover, the expression of GmolORs was significantly higher in the antennae of females than in those of males, with a peak in the antennae of 3-days-old adult females. GmolOR20 and GmolOR21 displayed no responses to any of the odorant compounds tested in the Xenopus oocyte system. GmolOR12 was tuned mainly to 5 of the 47 odorant components tested (including decanol, heptanal, octanal, nonanal, and decanal), and the response to aldehydes among the 5 components was the highest. Additionally, they all elicited female and male antennae electroantennogram responses, and the aldehydes elicited the highest response among the 5 components. These results suggested that GmolOR12 in the G. molesta olfactory system plays an important role in sensing aldehydes and that GmolOR12 is involved in sensing host-plant volatiles. These findings provide insight into the possibility of using host-plant volatiles for the control of G. molesta.

Comparison of Gut Bacterial Communities of Grapholita molesta (Lepidoptera: Tortricidae) Reared on Different Host Plants

“…Larvae usually harm the tender shoots of peach trees first, which causes the shoots' dieback. It will then drill into and eat the fruits of peaches, pears, and apples, resulting in fruit shedding, which seriously affects the product and quality of fruits, causing a great loss of economy [19,[21][22][23]. The fruit-and shoot-boring habit makes conventional insecticides poorly effective [22].…”

A Closer Look At Sex Pheromone Autodetection In The Oriental Fruit Moth

“…In male G. molesta 29% of the sensilla trichodea do not respond to pheromone [12], which is not far from the 38% that we report here. The presence of plant-volatile sensitive ORNs in males is believed to increase their probability of nding females, since these odorants have a synergic effect on male response to pheromone [14,16,17,49,50].…”

A closer look at sex pheromone autodetection in the Oriental fruit moth

“…In male G. molesta 29% of the sensilla trichodea do not respond to pheromone 12 , which is not far from the 38% that we report here. The presence of plant-volatile sensitive ORNs in males is believed to increase their probability of finding females, since these odorants have a synergic effect on male response to pheromone 14 , 16 , 17 , 49 , 50 . The low number of plant ORNs found in females probably resulted from testing only 3 plant compounds.…”