Effects of drought, temperature, herbivory, and genotype on plant–insect interactions in soybean (Glycine max)

Abstract

Climate change is predicted to cause continued increases in global temperatures, greater variability in precipitation and in some cases, more frequent insect pest outbreaks. Here we seek to understand how abiotic and biotic stresses associated with climate change can affect plant-herbivore interactions in a model crop species (soybean, Glycine max (L.) Merr.) by answering three questions: (1) Do the combined effects of abiotic and biotic stresses associated with climate change cause synergistic negative effects on plant biomass? (2) Can abiotic stress affect resistance of plants to insect herbivores? (3) Does genetic variation in plant traits modify a plant's response to stress? We performed three experiments in controlled growth environments using up to 51 soybean genotypes selected to vary in numerous traits associated with drought and resistance against pests (e.g., insect herbivores, nematodes, and pathogenic fungi), and up to 3 generalistfeeding herbivorous noctuid moth species (Helicoverpa zea, Heliothis virescens, and Spodoptera exigua) that commonly feed on soybean in North America. Drought and herbivory had the largest and the most consistent negative effects on plant performance, reducing the above-and below-ground biomass by 10-45 %, whereas increased temperature had little to no effect on plants. Drought also increased susceptibility to generalist noctuid herbivores, but these results varied dramatically in magnitude and direction among plant genotypes. Our experiments show that the effects of abiotic and biotic stress on soybean biomass were largely due to the additive effects of these stresses, and there exists substantial genetic variation in the soybean germplasm pool we studied that could be used as a source of parental stock in breeding new crops that can more effectively tolerate and resist the combined negative effects of insect herbivory and drought.

Positive and negative biotic interactions and invasive Triadica sebifera tolerance to salinity: a cross‐continent comparative study

“…The number of soil sources in each range was small (two) so it is possible that inclusion of a broader range of soils could yield different results. Finally, simulated herbivory does not reflect the complexity of plant–herbivore interactions such as variation in herbivore resistance with plant stress (Grinnan et al , Stephens et al ) or population origin (Huang et al , Wang et al ).…”

“…Th e number of soil sources in each range was small (two) so it is possible that inclusion of a broader range of soils could yield diff erent results. Finally, simulated herbivory does not refl ect the complexity of plant -herbivore interactions such as variation in herbivore resistance with plant stress (Grinnan et al 2013, Stephens et al 2013 or population origin (Huang et al 2012b, Wang et al 2012). Understanding exotic plant species niche expansions in the introduced range may help to reveal the mechanisms of biological invasions (Hierro et al 2005, Mitchell et al 2006.…”

Drought‐stress and plant resistance affect herbivore performance and proteome: the case of the green peach aphid Myzus persicae (Hemiptera: Aphididae)

“…Most likely, water management techniques will not increase the resistance conferred by the Rm2 gene. However, plant responses to drought are highly variable, and ecological consequences for plant-insect interactions are known to depend on plant species or genotype (Bjorkman, 2000;Evans et al, 2012;Grinnan et al, 2013). Thus, it is hypothesized that the implementation of different water use strategies could improve, with efficiency, the level of aphid protection conferred by genotypes with partial resistance.…”

“…On Brassica oleracea, the results are inconsistent, and the abundance either increases (Khan et al, 2010) or decreases (Simpson et al, 2012). On the other hand, in M. persicae changes in the proteome are induced with a switch of host plants (Francis et al, 2006), changes that might be also influenced by drought and host plant genotype within a species (Bjorkman, 2000;Gutbrodt et al, 2011;Evans et al, 2012;Grinnan et al, 2013).…”

Drones: Innovative Technology for Use in Precision Pest Management

“…Plants exposed to abiotic stressors, such as drought and nutrient deficiencies, are often more susceptible to biotic stressors. This holds true for a large variety of arthropod pests, such as spider mites (Garman and Kennedy 1949, Rodriguez and Neiswander 1949, Rodriguez 1951, Perring et al 1986, Stiefel et al 1992, Machado et al 2000, Abdel-Galil et al 2007, Nansen et al 2013, Ximénez-Embún et al 2017, aphids (Myers and Gratton 2006, Walter and Difonzo 2007, Lacoste et al 2015, and lepidopteran larvae (Gutbrodt et al 2011(Gutbrodt et al , 2012Grinnan et al 2013;Weldegergis et al 2015). Due to this well-established association between abiotic stressors and risk of arthropod pest outbreaks, it may be argued that precision application of abiotic stress relief, such as application of water and fertilizer, represents a meaningful approach to reducing the risk of outbreaks by some arthropod pests (Nansen et al 2013, West andNansen 2014).…”