Too much of a good thing? Hybrid necrosis as a by-product of plant immune system diversification

Botany ◽  
2009 ◽  
Vol 87 (11) ◽  
pp. 1013-1022 ◽  
Author(s):  
Kirsten Bomblies
Keyword(s):  
Immune System ◽  
Defense Responses ◽  
Plant Evolution ◽  
General Factor ◽  
Negative Consequences ◽  
Hybrid Necrosis ◽  
Genetic Incompatibility ◽  
Defense Proteins ◽  
Defense Strategies ◽  
Plant Immune System

Plants defend themselves against their enemies with an impressive arsenal of physical barriers, surveillance and defense proteins, enzymes, and toxic chemicals. Many different molecules are involved in the detection of invaders, suggesting that pathogen pressure selects for a broad array of defense strategies and a high diversity of recognition specificities in host species. Recent results in plants, however, show that immune system diversification can also have negative consequences; epistatic interactions among divergent immune system components can cause hybrid necrosis, a form of genetic incompatibility. This type of hybrid failure is frequently lethal, and characterized by the widespread induction of programmed cell death leading to tissue necrosis. In characterized examples, this is caused by hyperactivation of defense responses. Both the prevalence of hybrid necrosis in diverse plant taxa, and the growing indication that it may arise as a by-product of adaptation to the biotic environment, emphasize that it is likely a general factor in plant evolution. Since hybrid necrosis negatively impacts the progeny of certain crosses, divergence of the plant immune system may indirectly affect gene flow among populations, and perhaps contribute to the establishment or maintenance of species barriers.

scholarly journals Hybrid Incompatibility of the Plant Immune System: An Opposite Force to Heterosis Equilibrating Hybrid Performances

2021 ◽  
Vol 11 ◽  
Author(s):  
Vanesa Calvo-Baltanás ◽  
Jinge Wang ◽  
Eunyoung Chae
Keyword(s):  
Disease Resistance ◽  
Immune System ◽  
Plant Species ◽  
High Yield ◽  
Causative Role ◽  
Hybrid Necrosis ◽  
Core Element ◽  
Genetic Incompatibility ◽  
Trade Off ◽  
Role Based

Hybridization is a core element in modern rice breeding as beneficial combinations of two parental genomes often result in the expression of heterosis. On the contrary, genetic incompatibility between parents can manifest as hybrid necrosis, which leads to tissue necrosis accompanied by compromised growth and/or reduced reproductive success. Genetic and molecular studies of hybrid necrosis in numerous plant species revealed that such self-destructing symptoms in most cases are attributed to autoimmunity: plant immune responses are inadvertently activated in the absence of pathogenic invasion. Autoimmunity in hybrids predominantly occurs due to a conflict involving a member of the major plant immune receptor family, the nucleotide-binding domain and leucine-rich repeat containing protein (NLR; formerly known as NBS-LRR). NLR genes are associated with disease resistance traits, and recent population datasets reveal tremendous diversity in this class of immune receptors. Cases of hybrid necrosis involving highly polymorphic NLRs as major causes suggest that diversified R gene repertoires found in different lineages would require a compatible immune match for hybridization, which is a prerequisite to ensure increased fitness in the resulting hybrids. In this review, we overview recent genetic and molecular findings on hybrid necrosis in multiple plant species to provide an insight on how the trade-off between growth and immunity is equilibrated to affect hybrid performances. We also revisit the cases of hybrid weakness in which immune system components are found or implicated to play a causative role. Based on our understanding on the trade-off, we propose that the immune system incompatibility in plants might play an opposite force to restrict the expression of heterosis in hybrids. The antagonism is illustrated under the plant fitness equilibrium, in which the two extremes lead to either hybrid necrosis or heterosis. Practical proposition from the equilibrium model is that breeding efforts for combining enhanced disease resistance and high yield shall be achieved by balancing the two forces. Reverse breeding toward utilizing genomic data centered on immune components is proposed as a strategy to generate elite hybrids with balanced immunity and growth.

scholarly journals PlaD: A Transcriptomics Database for Plant Defense Responses to Pathogens, Providing New Insights into Plant Immune System

2018 ◽  
Vol 16 (4) ◽  
pp. 283-293 ◽  
Author(s):  
Huan Qi ◽  
Zhenhong Jiang ◽  
Kang Zhang ◽  
Shiping Yang ◽  
Fei He ◽  
...  
Keyword(s):  
Immune System ◽  
Plant Defense ◽  
Defense Responses ◽  
Plant Defense Responses ◽  
Plant Immune System

scholarly journals Method for the Production and Purification of Plant Immuno-Active Xylanase from Trichoderma

2021 ◽  
Vol 22 (8) ◽  
pp. 4214
Author(s):  
Gautam Anand ◽  
Meirav Leibman-Markus ◽  
Dorin Elkabetz ◽  
Maya Bar
Keyword(s):  
Immune System ◽  
Plant Defense ◽  
Plant Immunity ◽  
Xylanase Activity ◽  
Hydrolytic Enzymes ◽  
Adaptive Immune System ◽  
Defense Responses ◽  
Plant Defense Responses ◽  
Xylanase Production ◽  
Ideal System

Plants lack a circulating adaptive immune system to protect themselves against pathogens. Therefore, they have evolved an innate immune system based upon complicated and efficient defense mechanisms, either constitutive or inducible. Plant defense responses are triggered by elicitors such as microbe-associated molecular patterns (MAMPs). These components are recognized by pattern recognition receptors (PRRs) which include plant cell surface receptors. Upon recognition, PRRs trigger pattern-triggered immunity (PTI). Ethylene Inducing Xylanase (EIX) is a fungal MAMP protein from the plant-growth-promoting fungi (PGPF)–Trichoderma. It elicits plant defense responses in tobacco (Nicotiana tabacum) and tomato (Solanum lycopersicum), making it an excellent tool in the studies of plant immunity. Xylanases such as EIX are hydrolytic enzymes that act on xylan in hemicellulose. There are two types of xylanases: the endo-1, 4-β-xylanases that hydrolyze within the xylan structure, and the β-d-xylosidases that hydrolyze the ends of the xylan chain. Xylanases are mainly synthesized by fungi and bacteria. Filamentous fungi produce xylanases in high amounts and secrete them in liquid cultures, making them an ideal system for xylanase purification. Here, we describe a method for cost- and yield-effective xylanase production from Trichoderma using wheat bran as a growth substrate. Xylanase produced by this method possessed xylanase activity and immunogenic activity, effectively inducing a hypersensitive response, ethylene biosynthesis, and ROS burst.

scholarly journals Pivoting the Plant Immune System from Dissection to Deployment

Science ◽  
2013 ◽  
Vol 341 (6147) ◽  
pp. 746-751 ◽  
Author(s):  
Jeffery L. Dangl ◽  
Diana M. Horvath ◽  
Brian J. Staskawicz
Keyword(s):  
Immune System ◽  
Conceptual Understanding ◽  
Germ Plasm ◽  
Plant Diseases ◽  
Sequencing Technology ◽  
Plant Immune System ◽  
Rich Diversity ◽  
The World ◽  
The Rich ◽  
Molecular Components

Diverse and rapidly evolving pathogens cause plant diseases and epidemics that threaten crop yield and food security around the world. Research over the last 25 years has led to an increasingly clear conceptual understanding of the molecular components of the plant immune system. Combined with ever-cheaper DNA-sequencing technology and the rich diversity of germ plasm manipulated for over a century by plant breeders, we now have the means to begin development of durable (long-lasting) disease resistance beyond the limits imposed by conventional breeding and in a manner that will replace costly and unsustainable chemical controls.

Network organization of the plant immune system: from pathogen perception to robust defense induction

2021 ◽  
Author(s):  
Florent Delplace ◽  
Carine Huard‐Chauveau ◽  
Richard Berthomé ◽  
Dominique Roby
Keyword(s):  
Immune System ◽  
Network Organization ◽  
Plant Immune System ◽  
Defense Induction

scholarly journals Regulation of Plant Immunity by Nuclear Membrane-Associated Mechanisms

2021 ◽  
Vol 12 ◽  
Author(s):  
Yiling Fang ◽  
Yangnan Gu
Keyword(s):  
Immune System ◽  
Nuclear Membrane ◽  
Immune Activation ◽  
Core Protein ◽  
Current Knowledge ◽  
Plant Immunity ◽  
Defense Responses ◽  
Pathogen Resistance ◽  
Innate Immune ◽  
Nuclear Pore

Unlike animals, plants do not have specialized immune cells and lack an adaptive immune system. Instead, plant cells rely on their unique innate immune system to defend against pathogens and coordinate beneficial interactions with commensal and symbiotic microbes. One of the major convergent points for plant immune signaling is the nucleus, where transcriptome reprogramming is initiated to orchestrate defense responses. Mechanisms that regulate selective transport of nuclear signaling cargo and chromatin activity at the nuclear boundary play a pivotal role in immune activation. This review summarizes the current knowledge of how nuclear membrane-associated core protein and protein complexes, including the nuclear pore complex, nuclear transport receptors, and the nucleoskeleton participate in plant innate immune activation and pathogen resistance. We also discuss the role of their functional counterparts in regulating innate immunity in animals and highlight potential common mechanisms that contribute to nuclear membrane-centered immune regulation in higher eukaryotes.

Molecular evolution of plant immune system genes

2006 ◽  
Vol 22 (12) ◽  
pp. 662-670 ◽  
Author(s):  
P TIFFIN ◽  
D MOELLER
Keyword(s):  
Immune System ◽  
Molecular Evolution ◽  
Plant Immune System

scholarly journals Plant immune system uses demethylation

2013 ◽  
Vol 14 (3) ◽  
pp. 155-155
Author(s):  
Mary Muers
Keyword(s):  
Immune System ◽  
Plant Immune System

scholarly journals Proteomics of the Honeydew from the Brown Planthopper and Green Rice Leafhopper Reveal They Are Rich in Proteins from Insects, Rice Plant and Bacteria

Insects ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 582
Author(s):  
Jinghua Zhu ◽  
Kunmiao Zhu ◽  
Liang Li ◽  
Zengxin Li ◽  
Weiwei Qin ◽  
...  
Keyword(s):  
Immune System ◽  
Calcium Binding ◽  
Rice Plant ◽  
Brown Planthopper ◽  
Waste Product ◽  
Elongation Factor ◽  
Nilaparvata Lugens ◽  
Plant Responses ◽  
Green Rice Leafhopper ◽  
Plant Immune System

Honeydew is a watery fluid excreted by plant sap-feeding insects. It is a waste product for the insect hosts. However, it plays important roles for other organisms, such as serving as a nutritional source for beneficial insects and bacteria, as well as elicitors and effectors modulating plant responses. In this study, shotgun LC–MS/MS analyses were used to identify the proteins in the honeydew from two important rice hemipteran pests, the brown planthopper (Nilaparvata lugens, BPH) and green rice leafhopper (Nephotettix cincticeps, GRH). A total of 277 and 210 proteins annotated to insect proteins were identified in the BPH and GRH honeydews, respectively. These included saliva proteins that may have similar functions as the saliva proteins, such as calcium-binding proteins and apolipophorin, involved in rice plant defenses. Additionally, a total of 52 and 32 Oryza proteins were identified in the BPH and GRH honeydews, respectively, some of which are involved in the plant immune system, such as Pathogen-Related Protein 10, ascorbate peroxidase, thioredoxin and glutaredoxin. Coincidently, 570 and 494 bacteria proteins were identified from the BPH and GRH honeydews, respectively, which included several well-known proteins involved in the plant immune system: elongation factor Tu, flagellin, GroEL and cold-shock proteins. The results of our study indicate that the insect honeydew is a complex fluid cocktail that contains abundant proteins from insects, plants and microbes, which may be involved in the multitrophic interactions of plants–insects–microbes.

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