Select corn lines contain compounds that sicken, kill major crop pest
The compounds, called flavonoids, have an insecticidal effect on corn earworm larvae
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The flavonoids that provide insecticide-like protection to some corn lines against corn earworm larvae also provide pigments to the plants that show up in the silks, husks and kernels. Pictured here are the lines used in the research.
view moreCredit: Penn State
UNIVERSITY PARK, Pa. — The corn earworm causes the loss of more than 76 million bushels of corn in the United States annually, and there is mounting evidence that increasingly extreme weather events and temperatures will exacerbate the damage done to agricultural output by insect pests. Responding to the threat, a team of researchers at Penn State has demonstrated that genetic lines of corn have inherent compounds that serve as insecticides, protecting them from the larvae that feed on them.
In findings recently published online ahead of the March issue of Plant Stress, the researchers reported that corn earworm larvae feeding on the silks, husks and kernels of corn lines containing high levels of flavonoids — chemicals that play essential roles in many biological processes and responses to environmental factors in plants — grow much more slowly and many die, compared to larva feeding on corn lines without flavonoids.
In addition to increased mortality and reduced body weight, larvae feeding on high-flavonoid corn lines developed a leaky-gut-like syndrome, the researchers found, suggesting involvement of microbiome changes in the larval gut. Moreover, the expression of gut health-related genes was changed in larvae consuming the flavonoid-rich husks.
In the study, the researchers compared how corn earworm larvae survived on genetically identical strains, except for a few specific, known differences of corn — in this case, with some expressing high flavonoid content in silks, husks and kernels; some not. The corn, grown at the agronomy farm at Penn State’s Russell E. Larson Agricultural Research Center, included a line engineered to have a gene that triggers flavonoid production and a line that was conventionally bred to produce flavonoids, which was developed over the last two decades by Chopra’s lab from cross-breeding a mutant line of corn.
Researchers pointed out that they noticed “a stark difference” in mortality and bodyweight between corn earworm larvae feeding on flavonoid-overproducing lines as compared to control lines. Both the genetically engineered line and the line bred from the mutant had similar effects on the larvae.
“This research is important because it may be an early step toward the development of corn lines resistant to insect pests ideal for organic production,” said research team leader Surinder Chopra, professor of maize genetics. “These findings, which suggest a novel option for integrated pest management for corn earworm larvae, shows that high-flavonoid maize has the potential to be used in a breeding program to develop specialty corn lines tolerant of multiple insect pests.”
More research is needed before plant breeders could be expected to try developing flavonoid-producing corn lines that also protect against other insects for organic farmers, Chopra noted.
“Future studies will investigate the mechanisms behind flavonoid-mediated damage to the gut of corn earworm larvae and will explore the broader impacts of flavonoid content on plant-insect interactions,” he said.
The study was spearheaded by Debamalya Chatterjee, a former postdoctoral scholar in the Chopra lab who is currently an assistant professor at Skidmore College. Contributing to the research were Charles Colvin, undergraduate researcher in plant science; Tyler Lesko, doctoral student in the Department of Plant Science; Michelle Peiffer, research support assistant and lab manager in the Department of Entomology; and Gary Felton, professor and head of the Department of Entomology.
The U.S. Department of Agriculture’s National Institute of Food and Agriculture financially supported this work.
Journal
Plant Stress
Article Title
Plant defense against insect herbivory: Flavonoid-mediated growth inhibition of Helicoverpa zea
How nitrogen reshapes root system architecture in plants?
Higher Education Press
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view moreCredit: Xiujie LIU, Kai HUANG, Chengcai CHU
In soil, nitrogen (N), an essential macronutrient for plant growth, exhibits significant spatial heterogeneity. This necessitates plants to grapple with a complex array of environmental conditions in their quest for N sustenance. Roots, as the pivotal organs in N acquisition, manifest a remarkable morphological plasticity, including variations in the length and density of primary roots, lateral roots, and root hairs, in response to the form and content of available N, which is termed N-dependent root system architecture (RSA). For cultivated crops, the cultivation of an ideotype RSA, characterized by sensitive plasticity under diverse N conditions, is paramount for efficient N utilization, curtailment of N fertilizer inputs, and the realization of a green and sustainable agricultural development trajectory. What is the genetic basis of N-dependent RSA? The answers to this question will not only enrich the current understanding of the plants N utilization process, but also provide a treasure trove of genetic resources for targeted genetic modification, aimed at cultivating crops with ideotype RSA.
Prof. Chengcai Chu and his team from South China Agricultural University have systematically summarized the process of genetic basis of N-dependent RSA in Arabidopsis and major crops. Firstly, N sensing and signaling in plants is the fundamental to N-dependent RSA. The extracellular nitrate signal is primarily sensed and transduced into nucleus through the conserved NRT1-NLPs cascade across diverse plant taxa. Furthermore, long-distance N signal transduction between roots and shoots is mainly mediated by cytokinins and polypeptides, ensuring a harmonious interplay between different plant parts. Upon reception, these N signals intricately interact with phytohormones, such as auxin and brassinosteroid, either directly or indirectly influencing their synthesis, sensing, signaling, and distribution within the root system. This intricate hormonal crosstalk ultimately orchestrates the root developmental process in an N-dependent manner, reshaping the root architecture to suit varying N availabilities. While the majority of studies elucidating the genetic basis of N-dependent RSA have been conducted in the model plant Arabidopsis, our understanding of this process in crop plants remains nascent, let alone the implementation of genetic modification for cultivating ideotype RSA in these economically vital species. Fortunately, integration of advanced techniques like X-ray computed tomography and single cell analysis into plants research promises to unravel the genetic mysteries governing N-dependent RSA in crops. With these innovative tools at our disposal, the realization of ideotype RSA in future crop cultivars may soon transition from a distant aspiration to a tangible reality, heralding a new era in precision agriculture and sustainable food production.
This review has been published on the Journal of Frontiers of Agricultural Science and Engineering in 2025, 12(1): 3–15. DOI: 10.15302/J-FASE-2024587.
Journal
Frontiers of Agricultural Science and Engineering
Method of Research
Experimental study
Subject of Research
Not applicable
Article Title
The genetic basis of nitrogen-dependent root system architecture in plants
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