Aboveground Whitefly Infestation Modulates Transcriptional Levels of Anthocyanin Biosynthesis and Jasmonic Acid Signaling-Related Genes and Augments the Cope with Drought Stress of Maize.

Yong-Soon Park,Choong-Min Ryu,Dong-Won Bae,Jeum Kyu Hong

doi:10.1371/journal.pone.0143879

Abstract

Up to now, the potential underlying molecular mechanisms by which maize (Zea mays L.) plants elicit defense responses by infestation with a phloem feeding insect whitefly [Bemisia tabaci (Genn.)] have been barely elucidated against (a)biotic stresses. To fill this gap of current knowledge maize plants were infested with whitefly and these plants were subsequently assessed the levels of water loss. To understand the mode of action, plant hormone contents and the stress-related mRNA expression were evaluated. Whitefly-infested maize plants did not display any significant phenotypic differences in above-ground tissues (infested site) compared with controls. By contrast, root (systemic tissue) biomass was increased by 2-fold by whitefly infestation. The levels of endogenous indole-3-acetic acid (IAA), jasmonic acid (JA), and hydrogen peroxide (H2O2) were significantly higher in whitefly-infested plants. The biosynthetic or signaling-related genes for JA and anthocyanins were highly up-regulated. Additionally, we found that healthier plants were obtained in whitefly-infested plants under drought conditions. The weight of whitefly-infested plants was approximately 20% higher than that of control plants at 14 d of drought treatment. The drought tolerance-related genes, ZmbZIP72, ZmSNAC1, and ZmABA1, were highly expressed in the whitefly-infected plants. Collectively, our results suggest that IAA/JA-derived maize physiological changes and correlation of H2O2 production and water loss are modulated by above-ground whitefly infestation in maize plants.

Highlights

Plants protect themselves via their defensive mechanisms against diverse biotic and abiotic stresses [1]
The results showed that jasmonic acid (JA) was only detected in whitefly-infested leaf but not in control leaf (Fig 4C), and approximately two times higher JA levels were detected in whitefly-infested roots (Fig 4C)
Stimulates below-ground root growth but not above-ground shoot growth in maize; (2) whitefly infestation enhances anthocyanin pigmentation in roots; (3) plant hormones JA/indole-3-acetic acid (IAA) and hydrogen peroxide are endogenously synthesized in maize plants; and (4) whitefly infestation doi:10.1371/journal.pone.0143879.g006

Summary

Introduction

Plants protect themselves via their defensive mechanisms against diverse biotic and abiotic stresses [1]. Half a million insect species feed on plants, which constitutes one of the greatest biotic stresses [2]. Plant defense strategies against insect herbivory include enforcement of physical barriers and direct and indirect elicitation of inducible defenses [1]. Insects have evolved their feeding styles and behaviors during the last 350 million years to overcome plant defense strategies as well [3]. No visible damage to plant tissues is observed as a result of stylet piercing, and plant behaviors in response to piercing insects are not similar to those caused by mechanical wounding of plant tissues [5]. Aphids and whiteflies belong to the piercing and sucking insect herbivores group

Methods

Results

Conclusion