Pentyl leaf volatiles promote insect and pathogen resistance via enhancing ketol-mediated defense responses.

Plants emit an array of volatile organic compounds in response to stresses. Six-carbon green leaf volatiles (GLVs) and five-carbon pentyl leaf volatiles (PLVs) are fatty acid-derived compounds involved in intra- and inter-species communications. Unlike extensively studied GLVs, the biological activities of PLVs remain understudied.

and Differentially Regulate Maize Resistance to Anthracnose Leaf Blight and Insect Herbivores When Grown in Sterile versus Non-Sterile Soils.

Soil-borne spp. have been extensively studied for their biocontrol activities against pathogens and growth promotion ability in plants. However, the beneficial effect of on inducing resistance against insect herbivores has been underexplored.

Duplicated Copy Number Variant of the Maize 9-Lipoxygenase Improves 9,10-KODA-Mediated Resistance to Fall Armyworms.

Extensive genome structure variations, such as copy number variations (CNVs) and presence/absence variations, are the basis for the remarkable genetic diversity of maize; however, the effect of CNVs on maize herbivory defense remains largely underexplored. Here, we report that the naturally occurring duplication of the maize 9-lipoxygenase gene leads to increased resistance of maize to herbivory by fall armyworms (FAWs). Previously, we showed that ZmLOX5-derived oxylipins are required for defense against chewing insect herbivores and identified several inbred lines, including Yu796, that contained duplicated CNVs of , referred to as .

Maize OPR2 and LOX10 Mediate Defense against Fall Armyworm and Western Corn Rootworm by Tissue-Specific Regulation of Jasmonic Acid and Ketol Metabolism.

Foliage-feeding fall armyworm (FAW; ) and root-feeding western corn rootworm (WCR; ) are maize ( L.) pests that cause significant yield losses. Jasmonic acid (JA) plays a pivotal defense role against insects.

9,10-KODA, an α-ketol produced by the tonoplast-localized 9-lipoxygenase ZmLOX5, plays a signaling role in maize defense against insect herbivory.

13-Lipoxygenases (LOXs) initiate the synthesis of jasmonic acid (JA), the best-understood oxylipin hormone in herbivory defense. However, the roles of 9-LOX-derived oxylipins in insect resistance remain unclear. Here, we report a novel anti-herbivory mechanism mediated by a tonoplast-localized 9-LOX, ZmLOX5, and its linolenic acid-derived product, 9-hydroxy-10-oxo-12(Z),15(Z)-octadecadienoic acid (9,10-KODA).

A non-JA producing oxophytodienoate reductase functions in salicylic acid-mediated antagonism with jasmonic acid during pathogen attack.

Peroxisome-localized oxo-phytodienoic acid (OPDA) reductases (OPR) are enzymes converting 12-OPDA into jasmonic acid (JA). However, the biochemical and physiological functions of the cytoplasmic non-JA producing OPRs remain largely unknown. Here, we generated Mutator-insertional mutants of the maize OPR2 gene and tested its role in resistance to pathogens with distinct lifestyles.

Transcriptome and Oxylipin Profiling Joint Analysis Reveals Opposite Roles of 9-Oxylipins and Jasmonic Acid in Maize Resistance to Gibberella Stalk Rot.

Gibberella stalk rot caused by is one of the devastating diseases of maize that causes significant yield losses worldwide. The molecular mechanisms regulating defense against this pathogen remain poorly understood. According to recent studies, a major oxylipin hormone produced by 13-lipoxygenases (LOX) namely jasmonic acid (JA) has been associated with maize susceptibility to GSR.

Raman Spectroscopy as a Robust New Tool for Rapid and Accurate Evaluation of Drought Tolerance Levels in Both Genetically Diverse and Near-Isogenic Maize Lines.

Improving drought tolerance of crops has become crucial due to the current scenario of rapid climate change. In particular, development of new maize germplasm with increased drought tolerance is viewed as a major breeding goal to ensure sustainable food and feed production. Therefore, accurate rapid phenotyping techniques for selection of superior maize genotypes are required.

colonization of maize roots triggers rapid accumulation of 12-oxophytodienoate and two ᵧ-ketols in leaves as priming agents of induced systemic resistance.

Two oxylipins 12-OPDA (12-Oxo-10(),15()-phytodienoic acid) and an ᵧ-ketol, 9,10-KODA (10-oxo-9-hydroxy-12(), 15()-octadecadienoic acid) were recently identified as important long-distance-induced systemic resistance (ISR) signals in -treated maize. On the other hand, jasmonic acid (JA), long believed to be a major signal of ISR, was not involved, as the JA-deficient mutant, , retained the capacity for -triggered ISR. In order to further understand the biochemical basis for ISR priming in maize leaves, diverse oxylipins and phytohormones in the leaves of wild-type maize or ISR-deficient mutants treated with were quantified.

Relative contribution of LOX10, green leaf volatiles and JA to wound-induced local and systemic oxylipin and hormone signature in Zea mays (maize).

Green leaf volatiles (GLVs) and jasmonates (JAs) are the best-characterized groups of fatty acid-derived oxylipin signals that regulate wound-associated defenses. Beyond these two major groups of defense signals, plants produce an array of oxylipins in response to wounding, which possess potent signaling and/or insecticidal activities. In this study, we assessed the relative contribution of JAs and GLVs to wound-induced systemic signaling and the associated regulation of oxylipins in local and systemic tissues of maize (Zea mays).

12-Oxo-Phytodienoic Acid Acts as a Regulator of Maize Defense against Corn Leaf Aphid.

The corn leaf aphid (CLA; ) is a phloem sap-sucking insect that attacks many cereal crops, including maize (). We previously showed that the maize inbred line Mp708, which was developed by classical plant breeding, provides enhanced resistance to CLA. Here, using electrophysiological monitoring of aphid feeding behavior, we demonstrate that Mp708 provides phloem-mediated resistance to CLA.

New perspectives into jasmonate roles in maize.

It is well-known from the model dicotyledonous plants, Arabidopsis and tomato, that jasmonates (JAs) act as defense hormones in planta due to their potent ability to mediate defensive responses against insect/pathogen attacks or harsh environmental conditions. JA is also required for various developmental processes such as male fertility, seed maturation, root extension, and leaf senescence. In our recently published Plant Cell paper, the multiple roles of JA in the monocotyledonous agro-economically important model plant, maize, were investigated by comprehensive analysis of JA-deficient double mutant disrupted in the two oxophytodienoate reductase genes, OPR7 and OPR8.

The novel monocot-specific 9-lipoxygenase ZmLOX12 is required to mount an effective jasmonate-mediated defense against Fusarium verticillioides in maize.

Fusarium verticillioides is a major limiting factor for maize production due to ear and stalk rot and the contamination of seed with the carcinogenic mycotoxin fumonisin. While lipoxygenase (LOX)-derived oxylipins have been implicated in defense against diverse pathogens, their function in maize resistance against F. verticillioides is poorly understood.

Transposon mutagenesis reveals differential pathogenesis of Ralstonia solanacearum on tomato and Arabidopsis.

Ralstonia solanacearum causes a deadly wilting disease on a wide range of crops. To elucidate pathogenesis of this bacterium in different host plants, we set out to identify R. solanacearum genes involved in pathogenesis by screening random transposon insertion mutants of a highly virulent strain, Pss190, on tomato and Arabidopsis thaliana.