A successful defense of the narrow-leafed lupin against anthracnose involves quick and orchestrated reprogramming of oxidation-reduction, photosynthesis and pathogenesis-related genes

Transcriptional reprogramming in sound-treated Micro-Tom plants inoculated with Pseudomonas syringae pv. tomato DC3000

Sound vibrations (SV) are known to influence molecular and physiological processes that can improve crop performance and yield. In this study, the effects of three audible frequencies (100, 500 and 1000 Hz) at constant amplitude (90 dB) on tomato Micro-Tom physiological responses were evaluated 1 and 3 days post-treatment. Moreover, the potential use of SV treatment as priming agent for improved Micro-Tom resistance to Pseudomonas syringae pv. tomato DC3000 was tested by microarray. Results showed that the SV-induced physiological changes were frequency- and time-dependent, with the largest changes registered at 1000 Hz at day 3. SV treatments tended to alter the foliar content of photosynthetic pigments, soluble proteins, sugars, phenolic composition, and the enzymatic activity of polyphenol oxidase, peroxidase, superoxide dismutase and catalase. Microarray data revealed that 1000 Hz treatment is effective in eliciting transcriptional reprogramming in tomato plants grown under normal conditions, but particularly after the infection with Pst DC3000. Broadly, in plants challenged with Pst DC3000, the 1000 Hz pretreatment provoked the up-regulation of unique differentially expressed genes (DEGs) involved in cell wall reinforcement, phenylpropanoid pathway and defensive proteins. In addition, in those plants, DEGs associated with enhancing plant basal immunity, such as proteinase inhibitors, pathogenesis-related proteins, and carbonic anhydrase 3, were notably up-regulated in comparison with non-SV pretreated, infected plants. These findings provide new insights into the modulation of Pst DC3000-tomato interaction by sound and open up prospects for further development of strategies for plant disease management through the reinforcement of defense mechanisms in Micro-Tom plants.

Integrated transcriptome and proteome analyses unravel a series of early defence responses in Sarcandra glabra against Colletotrichum gloeosporioides

Anthracnose caused by Colletotrichum gloeosporioides critically threatens the growth and commercial cultivation of Sarcandra glabra . However, the defence responses and underlying mechanisms remain unclear. Herein, we aimed to investigate the molecular reprogramming in S. glabra leaves infected with C. gloeosporioides . Leaf tissues at 0, 24 and 48h post-inoculation (hpi) were analysed by combining RNA sequencing and Tandem Mass Tag-based liquid chromatography with tandem mass spectrometry. In total, 18 441 and 25 691 differentially expressed genes were identified at 24 and 48hpi compared to 0hpi (uninoculated control), respectively. In addition, 1240 and 1570 differentially abundant proteins were discovered at 24 and 48hpi compared to 0hpi, respectively. Correlation analysis revealed that transcription and translation levels were highly consistent regarding repeatability and expression. Analyses using databases KEGG and iPATH revealed tricitric acid cycle, glycolysis/gluconeogenesis and phenylpropanoid biosynthesis were induced, whereas photosynthesis and tryptophan were suppressed. Enzymatic activity assay results were consistent with the upregulation of defence-related enzymes including superoxide dismutases, catalases, peroxidases and chitinases. The transcriptome expression results were additionally validated by quantitative real-time polymerase chain reaction analyses. This study provides insights into the molecular reprogramming in S. glabra leaves during infection, which lay a foundation for investigating the mechanisms of host-Colletotrichum interactions and breeding disease-resistant plants.

Host Resistance to Virus Diseases Provides a Key Enabler towards Fast Tracking Gains in Grain Lupin Breeding

Four lupin species, Lupinus angustifolius, L. albus, L. luteus, and L. mutabilis, are grown as cool-season grain legume crops. Fifteen viruses infect them. Two of these, bean yellow mosaic virus (BYMV) and cucumber mosaic virus (CMV), cause diseases that threaten grain lupin production. Phytosanitary and cultural control measures are mainly used to manage them. However, breeding virus-resistant lupin cultivars provides an additional management approach. The need to develop this approach stimulated a search for virus resistance sources amongst cultivated lupin species and their wild relatives. This review focuses on the progress made in optimizing virus resistance screening procedures, identifying host resistances to BYMV, CMV, and additional viral pathogen alfalfa mosaic virus (AMV), and the inclusion of BYMV and CMV resistance within lupin breeding programs. The resistance types found in different combinations of virus and grain lupin species include localized hypersensitivity, systemic hypersensitivity, extreme resistance, and partial resistance to aphid or seed transmission. These resistances provide a key enabler towards fast tracking gains in grain lupin breeding. Where studied, their inheritance depended upon single dominant genes or was polygenic. Although transgenic virus resistance was incorporated into L. angustifolius and L. luteus successfully, it proved unstable. Priorities for future research are discussed.