Stressed Out: Why Does Ancient Maize Thrive in High-Stress Conditions?

Why is understanding stress response in maize so important? Maize, along with rice and wheat, provide at least 30% of calories to over 4.5 billion people Increases in flooding events has heavily impacted natural vegetation and crop production Combinatorial stresses, particularly flooding and herbivory, remain understudied for both modern and ancient verities of maize Ancient maize may be a superior genetic resource for flood-tolerant cor

The Tomato Strikes Back: Plant Response to Environmental Stress

Introduction Tomato is an important vegetable. Its production is threatened due to altered weather patterns which increase environmental stressors such as flooding1, 2 and herbivory3 to crops. Plants respond in many ways. Stressed plants strike back to environmental stress by altering their chemistry4: Volatile Organic Compounds (VOCs) emissions Defensive secondary metabolites2 Stress induced physiological changes in plants impact growth and development of insects. This study is broken into two experiments: The plant response to flooding stress The insect performance on flooded plant

Sometimes, When it Rains it Pours: How Does Flooding Alter Plant-Herbivore Relationships?

Flooding, an under-studied abiotic stressor, creates hostile soil conditions, including hypoxia, which hinder the growth and development of plants. Plants respond to abiotic and biotic stressors. A common response is the production of volatile organic compounds (VOCs), which modulate stress responses and mediate plant and insect interactions. Flooding causes significant losses in crops of agricultural and economic importance including tomato. Understanding how flooding impacts plant growth, plant chemistry, caterpillar performance and chemical mediated plant-herbivore interactions will create fundamental knowledge to an emerging challenge brought about by climate change and inform pest management decisions post flooding events. This study investigated how flooding alters tomato plant volatile emissions and affects caterpillar growth and performance

Exploration of Squash Plant Floral Volatiles Influencing Beetle Attraction

Flowers emit volatiles to attract pollinators, but these volatiles can also attract pest insects. Our study builds on earlier findings that showed that cucumber beetle attraction to squash flowers is mediated by volatile release and cucurbitacin accumulation (Theis, 2014, DOI: 10.3732/ajb.1400171). Of the three main domesticated squash species, only a few varieties of Cucurbita maxima had large quantities of floral volatiles and cucurbitacin (Andersen and Metcalf, 1987, doi: 10.1007/BF01020152); however, these studies were limited in the number of varieties that were examined. Here, we increased the number of C. maxima varieties examined, to identify patterns in floral volatile production, with the goal of identifying correlations between specific volatiles and beetle attraction. The findings from this study support a larger project, Fighting Fire with FIRE: Exploiting Corn Rootworm Attraction to Manipulate Pest Behavior

Differential regulation of cytochrome P450 genes associated with biosynthesis and detoxification in bifenthrin-resistant populations of navel orangewom (Amyelois transitella).

Pyrethroid resistance was first reported in 2013 for the navel orangeworm, Amyelois transitella, but the genetic underpinnings of pyrethroid resistance are unknown. We investigated the role of cytochrome P450 monooxygenases (P450s) belonging to the CYP3 and CYP4 clans using colonies derived from individuals collected in 2016 from almond orchards in two counties. One colony (ALM) originated from an almond orchard in Madera County with no reported pyrethroid resistance and the second colony (R347) originated from the same Kern County orchard where pyrethroid resistance was first reported. We used high-throughput quantitative real-time PCR (qRT-PCR) analyses of 65 P450s in the CYP3 and CYP4 clans of A. transitella to identify P450s induced by bifenthrin and associated with pyrethroid resistance. Nine P450s were constitutively overexpressed in R347 compared to ALM, including CYP6AE54 (11.7-fold), belonging to a subfamily associated with metabolic pesticide detoxification in Lepidoptera and CYP4G89 (33-fold) belonging to a subfamily associated with cuticular hydrocarbon (CHC) synthesis and resistance via reduced pesticide penetrance. Cuticular hydrocarbons analysis revealed that R347 produced twice as many total CHCs in the egg and adult stages as ALM. Topical toxicity bioassays for R347 determined that egg mortality was reduced at low bifenthrin concentrations and larval mortality was reduced at high concentrations of bifenthrin compared to ALM. Our discovery of both changes in metabolism and production of CHCs for R347 have implications for the possible decreased efficacy of other classes of insecticide used to control this insect. The threat of widespread pyrethroid resistance combined with the potential for cross-resistance to develop through the mechanism of reduced penetrance warrants developing management strategies that facilitate insecticide passage across the cuticle