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Jayaraman J, Yoon M, Hemara LM, Bohne D, Tahir J, Chen RKY, Brendolise C, Rikkerink EHA, Templeton MD. Contrasting effector profiles between bacterial colonisers of kiwifruit reveal redundant roles converging on PTI-suppression and RIN4. THE NEW PHYTOLOGIST 2023; 238:1605-1619. [PMID: 36856342 DOI: 10.1111/nph.18848] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 02/14/2023] [Indexed: 06/18/2023]
Abstract
Testing effector knockout strains of the Pseudomonas syringae pv. actinidiae biovar 3 (Psa3) for reduced in planta growth in their native kiwifruit host revealed a number of nonredundant effectors that contribute to Psa3 virulence. Conversely, complementation in the weak kiwifruit pathogen P. syringae pv. actinidifoliorum (Pfm) for increased growth identified redundant Psa3 effectors. Psa3 effectors hopAZ1a and HopS2b and the entire exchangeable effector locus (ΔEEL; 10 effectors) were significant contributors to bacterial colonisation of the host and were additive in their effects on virulence. Four of the EEL effectors (HopD1a, AvrB2b, HopAW1a and HopD2a) redundantly contribute to virulence through suppression of pattern-triggered immunity (PTI). Important Psa3 effectors include several redundantly required effectors early in the infection process (HopZ5a, HopH1a, AvrPto1b, AvrRpm1a and HopF1e). These largely target the plant immunity hub, RIN4. This comprehensive effector profiling revealed that Psa3 carries robust effector redundancy for a large portion of its effectors, covering a few functions critical to disease.
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Affiliation(s)
- Jay Jayaraman
- The New Zealand Institute for Plant and Food Research Ltd, Mt. Albert Research Centre, Auckland, 1025, New Zealand
| | - Minsoo Yoon
- The New Zealand Institute for Plant and Food Research Ltd, Mt. Albert Research Centre, Auckland, 1025, New Zealand
| | - Lauren M Hemara
- The New Zealand Institute for Plant and Food Research Ltd, Mt. Albert Research Centre, Auckland, 1025, New Zealand
- School of Biological Sciences, University of Auckland, Auckland, 1010, New Zealand
| | - Deborah Bohne
- The New Zealand Institute for Plant and Food Research Ltd, Mt. Albert Research Centre, Auckland, 1025, New Zealand
| | - Jibran Tahir
- The New Zealand Institute for Plant and Food Research Ltd, Mt. Albert Research Centre, Auckland, 1025, New Zealand
| | - Ronan K Y Chen
- The New Zealand Institute for Plant and Food Research Ltd, Food Industry Science Centre, Palmerston North, 4472, New Zealand
| | - Cyril Brendolise
- The New Zealand Institute for Plant and Food Research Ltd, Mt. Albert Research Centre, Auckland, 1025, New Zealand
| | - Erik H A Rikkerink
- The New Zealand Institute for Plant and Food Research Ltd, Mt. Albert Research Centre, Auckland, 1025, New Zealand
| | - Matthew D Templeton
- The New Zealand Institute for Plant and Food Research Ltd, Mt. Albert Research Centre, Auckland, 1025, New Zealand
- School of Biological Sciences, University of Auckland, Auckland, 1010, New Zealand
- Bioprotection Aotearoa, Lincoln, 7647, New Zealand
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Lee HY, Back K. 2-Hydroxymelatonin Promotes Seed Germination by Increasing Reactive Oxygen Species Production and Gibberellin Synthesis in Arabidopsis thaliana. Antioxidants (Basel) 2022; 11:antiox11040737. [PMID: 35453427 PMCID: PMC9028592 DOI: 10.3390/antiox11040737] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/01/2022] [Accepted: 04/06/2022] [Indexed: 01/27/2023] Open
Abstract
It was recently reported that 2-hydroxymelatonin (2-OHM) is responsible for inducing reactive oxygen species (ROS) in plants. ROS are crucial molecules that promote germination through interaction with hormones such as gibberellic acid (GA). In this study, to confirm the pro-oxidant role of 2-OHM, we investigated its effect on seed germination in Arabidopsis thaliana (L.) Heynh. Columbia-0. We found that 2-OHM treatment stimulated seed germination by 90% and 330% in non-dormant and dormant seeds, respectively, whereas melatonin marginally increased germination (~13%) in both seed types compared to untreated control seeds. The germination promotion effects of exogenous 2-OHM treatment were due to increased ROS production followed by the induction of GA synthesis and expression of responsive genes. Accordingly, melatonin 2-hydroxylase (M2H), the gene responsible for 2-OHM synthesis, was strictly expressed only during the germination process. Further molecular genetic analyses using m2h knockout mutant and M2H overexpression clearly supported an increase in ROS triggered by 2-OHM, followed by increased expression of GA-related genes, which shortened the time to germination. Notably, 2-OHM application to m2h knockout mutant seeds fully recovered germination to levels comparable to that of the wild type, whereas melatonin treatment failed to increase germination. Together, these results indicate that 2-OHM is a pivotal molecule that triggers increased ROS production during seed germination, thereby enhancing germination via the GA pathway in Arabidopsis thaliana.
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Jayaraman J, Chatterjee A, Hunter S, Chen R, Stroud EA, Saei H, Hoyte S, Deroles S, Tahir J, Templeton MD, Brendolise C. Rapid Methodologies for Assessing Pseudomonas syringae pv. actinidiae Colonization and Effector-Mediated Hypersensitive Response in Kiwifruit. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:880-890. [PMID: 33834857 DOI: 10.1094/mpmi-02-21-0043-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The infection of Pseudomonas syringae pv. actinidiae in kiwifruit is currently assessed by numerous methodologies, each with their own limitations. Most studies are based on either a laborious method of growth quantification of the pathogen or qualitative assessments by visual scoring following stem or cutting inoculation. Additionally, when assessing for resistance against specific pathogen effectors, confounding interactions between multiple genes in the pathogen can make mapping resistance phenotypes nearly impossible. Here, we present robust alternative methods to quantify pathogen load based on rapid bacterial DNA quantification by PCR, the use of Pseudomonas fluorescens, and a transient reporter eclipse assay for assessing resistance conferred by isolated bacterial avirulence genes. These assays compare well with bacterial plate counts to assess bacterial colonization as a result of plant resistance activation. The DNA-based quantification, when coupled with the P. fluorescens and reporter eclipse assays to independently identify bacterial avirulence genes, is rapid, highly reproducible, and scalable for high-throughput screens of multiple cultivars or genotypes. Application of these methodologies will allow rapid and high-throughput identification of resistant cultivars and the bacterial avirulence genes they recognize, facilitating resistance gene discovery for plant breeding programs.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Jay Jayaraman
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
- Bio-Protection Research Centre, Lincoln, New Zealand
| | - Abhishek Chatterjee
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
| | - Shannon Hunter
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
| | - Ronan Chen
- The New Zealand Institute for Plant and Food Research Limited, Palmerston North, New Zealand
| | - Erin A Stroud
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Hassan Saei
- The New Zealand Institute for Plant and Food Research Limited, Palmerston North, New Zealand
| | - Stephen Hoyte
- The New Zealand Institute for Plant and Food Research Limited, Ruakura Research Centre, Hamilton, New Zealand
| | - Simon Deroles
- The New Zealand Institute for Plant and Food Research Limited, Palmerston North, New Zealand
| | - Jibran Tahir
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
| | - Matthew D Templeton
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
- Bio-Protection Research Centre, Lincoln, New Zealand
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Cyril Brendolise
- The New Zealand Institute for Plant and Food Research Limited, Auckland, New Zealand
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Yang G, Wang C, Wang Y, Guo Y, Zhao Y, Yang C, Gao C. Overexpression of ThVHAc1 and its potential upstream regulator, ThWRKY7, improved plant tolerance of Cadmium stress. Sci Rep 2016; 6:18752. [PMID: 26744182 PMCID: PMC4705465 DOI: 10.1038/srep18752] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 11/25/2015] [Indexed: 01/03/2023] Open
Abstract
As one of the most toxic heavy metals in the environment, cadmium (Cd) poses a severe threat to plant growth. We previously reported that overexpression of the Tamarix hispida V-ATPase c subunit (ThVHAc1) improved the Cd tolerance of Saccharomyces cerevisiae. In the current study, we further explored the Cd tolerance conferred by ThVHAc1 in Arabidopsis and T. hispida. ThVHAc1 transgenic Arabidopsis had higher seed germination, biomass, and chlorophyll content under CdCl2 treatment. In Cd-stressed plants, overexpression of ThVHAc1 significantly improved V-ATPase activity and affected the expression of other V-ATPase subunit-encoding genes. Intriguingly, the lower level of ROS accumulation in ThVHAc1-overexpressing lines under CdCl2 treatment demonstrated that ThVHAc1 may modulate Cd stress tolerance by regulating ROS homeostasis. Transient expression of ThVHAc1 in T. hispida further confirmed these findings. Furthermore, promoter analysis and yeast one-hybrid assay revealed that the transcription factor ThWRKY7 can specifically bind to the WRKY cis-element in the ThVHAc1 promoter. ThWRKY7 exhibited similar expression patterns as ThVHAc1 under CdCl2 treatment and improved Cd tolerance, suggesting that ThWRKY7 may be an upstream regulatory gene of ThVHAc1. Therefore, our results show that the combination of ThVHAc1 and its upstream regulator could be used to improve Cd stress tolerance in woody plants.
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Affiliation(s)
- Guiyan Yang
- State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University), 26 Hexing Road, Harbin 150040, China
- Laboratory of Walnut Research Center, College of Forestry, Northwest A & F University, Yangling, 712100 Shaanxi, China
| | - Chao Wang
- State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University), 26 Hexing Road, Harbin 150040, China
| | - Yucheng Wang
- State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University), 26 Hexing Road, Harbin 150040, China
| | - Yucong Guo
- State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University), 26 Hexing Road, Harbin 150040, China
| | - Yulin Zhao
- State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University), 26 Hexing Road, Harbin 150040, China
| | - Chuanping Yang
- State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University), 26 Hexing Road, Harbin 150040, China
| | - Caiqiu Gao
- State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University), 26 Hexing Road, Harbin 150040, China
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Gregersen PL, Culetic A, Boschian L, Krupinska K. Plant senescence and crop productivity. PLANT MOLECULAR BIOLOGY 2013; 82:603-22. [PMID: 23354836 DOI: 10.1007/s11103-013-0013-8] [Citation(s) in RCA: 256] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 01/15/2013] [Indexed: 05/18/2023]
Abstract
Senescence is a developmental process which in annual crop plants overlaps with the reproductive phase. Senescence might reduce crop yield when it is induced prematurely under adverse environmental conditions. This review covers the role of senescence for the productivity of crop plants. With the aim to enhance productivity, a number of functional stay-green cultivars have been selected by conventional breeding, in particular of sorghum and maize. In many cases, a positive correlation between leaf area duration and yield has been observed, although in a number of other cases, stay-green cultivars do not display significant effects with regards to productivity. In several crops, the stay-green phenotype is observed to be associated with a higher drought resistance and a better performance under low nitrogen conditions. Among the approaches used to achieve stay-green phenotypes in transgenic plants, the expression of the IPT gene under control of senescence-associated promoters has been the most successful. The promoters employed for senescence-regulated expression contain cis-elements for binding of WRKY transcription factors and factors controlled by abscisic acid. In most crops transformed with such constructs the stay-green character has led to increased biomass, but only in few cases to increased seed yield. A coincidence of drought stress resistance and stay-green trait is observed in many transgenic plants.
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Affiliation(s)
- Per L Gregersen
- Department of Molecular Biology and Genetics, Aarhus University, Forsoegsvej 1, 4200 Slagelse, Denmark
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