Plant Resistance and Insect Bioecology and Nutrition

Understanding the mechanisms involved in host plant resistance opens the way for improved resistance breeding programs by using the traits involved as markers. Pest management is a major problem in cultivation of ornamentals. Gladiolus (Gladiolus hybridus L.) is an economically important ornamental in the Netherlands. Gladiolus is especially sensitive to attack by western flower thrips (Frankliniella occidentalis (Pergande) (Thysanoptera:Thripidae)). The objective of this study was, therefore, to investigate morphological and chemical markers for resistance breeding to western flower thrips in Gladiolus varieties. We measured thrips damage of 14 Gladiolus varieties in a whole-plant thrips bioassay and related this to morphological traits with a focus on papillae density. Moreover, we studied chemical host plant resistance to using an eco-metabolomic approach comparing the 1H NMR profiles of thrips resistant and susceptible varieties representing a broad range of papillae densities. Thrips damage varied strongly among varieties: the most susceptible variety showed 130 times more damage than the most resistant one. Varieties with low thrips damage had shorter mesophylls and epidermal cells, as well as a higher density of epicuticular papillae. All three traits related to thrips damage were highly correlated with each other. We observed a number of metabolites related to resistance against thrips: two unidentified triterpenoid saponins and the amino acids alanine and threonine. All these compounds were highly correlated amongst each other as well as to the density of papillae. These correlations suggest that papillae are involved in resistance to thrips by producing and/or storing compounds causing thrips resistance. Although it is not possible to distinguish the individual effects of morphological and chemical traits statistically, our results show that papillae density is an easy marker in Gladiolus-breeding programs targeted at increased resistance to thrips.

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Comparative Effectiveness of Potential Elicitors of Soybean Plant Resistance Against Spodoptera Littoralis and Their Effects on Secondary Metabolites and Antioxidant Defense System

Gesunde Pflanzen ◽

10.1007/s10343-021-00546-6 ◽

2021 ◽

Author(s):

Heba I. Mohamed ◽

Abdel Haleem M. A. Mohammed ◽

Neven M. Mohamed ◽

Naglaa A. Ashry ◽

Laila M. Zaky ◽

...

Keyword(s):

Secondary Metabolites ◽

Plant Resistance ◽

Comparative Effectiveness ◽

Spodoptera Littoralis ◽

Antioxidant Defense ◽

Antioxidant Defense System ◽

Soybean Plant ◽

Defense System

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Comparative TMT Proteomic Analysis Unveils Unique Insights into Helicoverpa armigera (Hübner) Resistance in Cajanus scarabaeoides (L.) Thouars

International Journal of Molecular Sciences ◽

10.3390/ijms22115941 ◽

2021 ◽

Vol 22 (11) ◽

pp. 5941

Author(s):

Abigail Ngugi-Dawit ◽

Isaac Njaci ◽

Thomas J.V. Higgins ◽

Brett Williams ◽

Sita R. Ghimire ◽

...

Keyword(s):

Host Plant ◽

Helicoverpa Armigera ◽

Plant Resistance ◽

Host Plant Resistance ◽

Proteomic Analysis ◽

Artificial Diet ◽

Growth Stages ◽

Genetic Base ◽

Helicoverpa Armígera ◽

Helicoverpa Armigera Hubner

Pigeonpea [Cajanus cajan (L.) Millspaugh] is an economically important legume playing a crucial role in the semi-arid tropics. Pigeonpea is susceptible to Helicoverpa armigera (Hübner), which causes devastating yield losses. This pest is developing resistance to many commercially available insecticides. Therefore, crop wild relatives of pigeonpea, are being considered as potential sources of genes to expand the genetic base of cultivated pigeonpea to improve traits such as host plant resistance to pests and pathogens. Quantitative proteomic analysis was conducted using the tandem mass tag platform to identify differentially abundant proteins between IBS 3471 and ICPL 87 tolerant accession and susceptible variety to H. armigera, respectively. Leaf proteome were analysed at the vegetative and flowering/podding growth stages. H. armigera tolerance in IBS 3471 appeared to be related to enhanced defence responses, such as changes in secondary metabolite precursors, antioxidants, and the phenylpropanoid pathway. The development of larvae fed on an artificial diet with IBS 3471 lyophilised leaves showed similar inhibition with those fed on an artificial diet with quercetin concentrations with 32 mg/25 g of artificial diet. DAB staining (3,3’-diaminobenzidine) revealed a rapid accumulation of reactive oxygen species in IBS 3471. We conclude that IBS 3471 is an ideal candidate for improving the genetic base of cultivated pigeonpea, including traits for host plant resistance.

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MicroRNA319a regulates plant resistance to Sclerotinia stem rot

Journal of Experimental Botany ◽

10.1093/jxb/erab070 ◽

2021 ◽

Author(s):

Weiguo Dong ◽

Wenqing Ren ◽

Xuan Wang ◽

He Yuke

Keyword(s):

Plant Resistance ◽

Host Susceptibility ◽

Stem Rot ◽

Sclerotinia Stem Rot ◽

Sequencing Data ◽

Mobility Shift ◽

Expression Levels ◽

Affected Plant ◽

Mobility Shift Assay ◽

Rot Disease

Abstract MicroRNA319a (miR319a) controls cell division arrest in plant leaves by inhibiting the expression of TCP (TEOSINTE BRANCHED 1/CYCLOIDEA/PCF) family genes. However, it is unclear whether miR319a influences infections by necrotrophic pathogens and host susceptibility. In this study, we revealed that miR319a affected plant resistance to stem rot disease of Sclerotinia sclerotiorum. In the plants of Brassica rapa infected with S. sclerotiorum, miR319a levels increased while expression levels of several BraTCP genes significantly decreased compared with those of the uninfected plants. The overexpression of BraMIR319a in B. rapa increased the susceptibility of the plants to S. sclerotiorum and aggravated stem rot disease, whereas the overexpression of BraTCP4-1 promoted the plant resistance. Our RNA-sequencing data revealed a potential relationship between miR319a and pathogen-related WRKY genes. Chromatin immunoprecipitation (ChIP) assay, electrophoretic mobility shift assay (EMSA) and reporter transaction assay showed that BraTCP4-1 was bound to the promoters of WRKY75, WRKY70, and WRKY33 genes and directly activated these pathogen-related genes. Moreover, the expression levels of WRKY75, WRKY70, and WRKY33 in the plants overexpressing BraMIR319a declined significantly whereas those of the plants overexpressing BraTCP4-1 increased significantly. These results suggest that miR319a and its targeted gene BraTCP4 regulate stem rot resistance through pathways of WRKY genes.

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