Cover Crop Soil Legacies Alter Phytochemistry and Resistance to Fall Armyworm (Lepidoptera: Noctuidae) in Maize

Davidson-Lowe, Elizabeth; Ray, Swayamjit; Murrell, Ebony G.; Kaye, Jason P.; Ali, Jared G.

doi:10.1093/ee/nvab047

Cited by 9 publications

(18 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, nitrogen is also a limiting nutrient to herbivore growth and nitrogen availability is associated with fall armyworm performance and behavior. Fall armyworm typically perform better on and prefer plants that are grown in nitrogen-rich soils (Wiseman et al, 1973;Davidson-Lowe et al, 2021). Recent studies demonstrate that phosphorous plays a functional role in defense hormone signaling and is also involved in plant-microbe associations that confer resistance to herbivores and pathogens (Mustafa et al, 2016;Murrell et al, 2019;Chan et al, 2021).…”

Section: Discussionmentioning

confidence: 99%

Plant Nutrition Influences Resistant Maize Defense Responses to the Fall Armyworm (Spodoptera frugiperda)

et al. 2022

Self Cite

View full text Add to dashboard Cite

Plants are often confronted by different groups of herbivores, which threaten their growth and reproduction. However, they are capable of mounting defenses against would-be attackers which may be heightened upon attack. Resistance to insects often varies among plant species, with different genotypes exhibiting unique patterns of chemical and physical defenses. Within this framework, plant access to nutrients may be critical for maximal functioning of resistance mechanisms and are likely to differ among plant genotypes. In this study, we aimed to test the hypothesis that access to nutrition would alter the expression of plant resistance to insects and alter insect performance in a manner consistent with fertilization regime. We used two maize (Zea mays) genotypes possessing different levels of resistance and the fall armyworm (Spodoptera frugiperda) as model systems. Plants were subjected to three fertilization regimes prior to assessing insect-mediated responses. Upon reaching V4 stage, maize plants were separated into two groups, one of which was infested with fall armyworm larvae to induce plant defenses. Plant tissue was collected and used in insect bioassays and to measure the expression of defense-related genes and proteins. Insect performance differed between the two plant genotypes substantially. For each genotype, fertilization altered larval performance, where lower fertilization rates hindered larval growth. Induction of plant defenses by prior herbivory substantially reduced naïve fall armyworm growth in both genotypes. The effects between fertilization and induced defenses were complex, with low fertilization reducing induced defenses in the resistant maize. Gene and protein expression patterns differed between the genotypes, with herbivory often increasing expression, but differing between fertilization levels. The soluble protein concentrations did not change across fertilization levels but was higher in the susceptible maize genotype. These results demonstrate the malleability of plant defenses and the cascading effects of plant nutrition on insect herbivory.

show abstract

Section: Discussionmentioning

confidence: 99%

Plant Nutrition Influences Resistant Maize Defense Responses to the Fall Armyworm (Spodoptera frugiperda)

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…It has also been shown that maize defense compounds are altered by AMF colonization of plant roots [45][46][47] and by plant fertilization [48][49][50]. Furthermore, soil legacies left behind by different cover crop species have been shown to differentially alter plant nutrition, AMF colonization, and regulation in JA and SA defense genes in subsequent maize plants, as well as alter the feeding and behavior of FAW larvae toward those maize plants [51].…”

Section: Introductionmentioning

confidence: 99%

Nutrition vs association: plant defenses are altered by arbuscular mycorrhizal fungi association not by nutritional provisioning alone

et al. 2022

Self Cite

View full text Add to dashboard Cite

Background While it is known that arbuscular mycorrhizal fungi (AMF) can improve nutrient acquisition and herbivore resistance in crops, the mechanisms by which AMF influence plant defense remain unknown. Plants respond to herbivory with a cascade of gene expression and phytochemical biosynthesis. Given that the production of defensive phytochemicals requires nutrients, a commonly invoked hypothesis is that the improvement to plant defense when grown with AMF is simply due to an increased availability of nutrients. An alternative hypothesis is that the AMF effect on herbivory is due to changes in plant defense gene expression that are not simply due to nutrient availability. In this study, we tested whether changes in plant defenses are regulated by nutritional provisioning alone or the response of plant to AMF associations. Maize plants grown with or without AMF and with one of three fertilizer treatments (standard, 2 × nitrogen, or 2 × phosphorous) were infested with fall armyworm (Spodoptera frugiperda; FAW) for 72 h. We measured general plant characteristics (e.g. height, number of leaves), relative gene expression (rtPCR) of three defensive genes (lox3, mpi, and pr5), total plant N and P nutrient content, and change in FAW mass per plant. Results We found that AMF drove the defense response of maize by increasing the expression of mpi and pr5. Furthermore, while AMF increased the total phosphorous content of maize it had no impact on maize nitrogen. Fertilization alone did not alter upregulation of any of the 3 induced defense genes tested, suggesting the mechanism through which AMF upregulate defenses is not solely via increased N or P plant nutrition. Conclusion This work supports that maize defense may be optimized by AMF associations alone, reducing the need for artificial inputs when managing FAW.

show abstract

“…The benefits of cover crops are commonly estimated during the cover cropping season [ 4 , 5 ], and include, but are not limited to weed suppression [ 6 ], reduction of soil erosion [ 7 , 8 ], enhancement of soil organic matter [ 9 , 10 ], and even pest management [ 3 , 4 ]. Recent studies have also started to show that some of these effects, especially in pest management, can cascade from cover to the cash crop growing seasons [ 11 , 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

“…The management of FAW in recent years has ranged from the use of synthetic pesticides to biopesticides, cultural control, and biological control [ 20 ]. However, studies have also shown that cover crops can prime the defense of subsequent cash crops against herbivores [ 4 , 11 ]. For example, [ 3 ] showed that arbuscular mycorrhizal fungi (AMF) inoculated cover crops had significantly better fitness and received lower levels of herbivory compared to control plants, more specifically on the incidence and damage by FAW.…”

Section: Introductionmentioning

confidence: 99%

“…We then followed up these experiments by examining physical (wax, trichomes) and chemical (poly phenol oxidase activity) in the cash crop. We hypothesized that cover crops would have a positive cascading effect on the subsequent cash crop defense against herbivores ( S. frugiperda ), possibly through modified plant–soil feedback that enhances the constitutive defenses in the cash crop [ 3 , 11 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cascading Effects of Cover Crops on the Subsequent Cash Crop Defense against the Polyphagous Herbivore Fall Armyworm (Spodoptera frugiperda)

Fajemisin

Racelis

Kariyat

2023

Insects

View full text Add to dashboard Cite

Recent studies have started to show that the benefits of cover crops can cascade to the cash crop growing seasons. However, the impact of cover crops on the subsequent cash crop defense against herbivores is not well understood. To test this, we conducted a field and laboratory study to assess the possible cascading effects of cover crops such as Vigna unguiculata, Sorghum drummondii, Raphanus sativus, and Crotalaria juncea on the subsequent cash crop (Sorghum bicolor) defense against the notorious polyphagous herbivore fall armyworm (Spodoptera frugiperda) across three farms in the Lower Rio Grande Valley. Our field and laboratory studies showed that the cash crop planted in the cover crop treatment differentially affected S. frugiperda. More specifically, we found that cover crops have positive effects on the growth and development of S. frugiperda on the subsequent cash crop, including both larval and pupal parameters. However, our experiments on physical and chemical defenses in cash crops failed to show any significant differences between cover and control. Collectively, our results add an additional line of evidence on the effects of cover crops on pest dynamics outside the cash crop season, a key consideration for the selection and management of cover crops and cash crops, whose underlying mechanisms need to be examined further.

show abstract

Cover Crop Soil Legacies Alter Phytochemistry and Resistance to Fall Armyworm (Lepidoptera: Noctuidae) in Maize

Cited by 9 publications

References 64 publications

Plant Nutrition Influences Resistant Maize Defense Responses to the Fall Armyworm (Spodoptera frugiperda)

Plant Nutrition Influences Resistant Maize Defense Responses to the Fall Armyworm (Spodoptera frugiperda)

Nutrition vs association: plant defenses are altered by arbuscular mycorrhizal fungi association not by nutritional provisioning alone

Cascading Effects of Cover Crops on the Subsequent Cash Crop Defense against the Polyphagous Herbivore Fall Armyworm (Spodoptera frugiperda)

Contact Info

Product

Resources

About