Recent advances in bio‐chemical, molecular and physiological aspects of membrane lipid derivatives in plant pathology

Abstract

Plant pathogens pose a significant threat to the food industry and food security accounting for 10-40% crop losses annually on a global scale. Economic losses from plant diseases are estimated at $300B for major food crops and are associated with reduced food availability and accessibility and also high food costs. Although strategies exist to reduce the impact of diseases in plants, many of these introduce harmful chemicals to our food chain. Therefore, it is important to understand and utilize plants' immune systems to control plant pathogens to enable more sustainable agriculture. Lipids are core components of cell membranes and as such are part of the first line of defense against pathogen attack. Recent developments in omics technologies have advanced our understanding of how plant membrane lipid biosynthesis, remodelling and/or signalling modulate plant responses to infection. Currently, there is limited information available in the scientific literature concerning lipid signalling targets and their biochemical and physiological consequences in response to plant pathogens. This review focusses on the functions of membrane lipid derivatives and their involvement in plant responses to pathogens as biotic stressors. We describe major plant defense systems including systemic-acquired resistance, basal resistance, hypersensitivity and the gene-for-gene concept in this context. 1 | INTRODUCTION The advancement in global agricultural production, the food industry and food security necessitates consideration of the impact of infectious pathogens on plants. This is because pathogens are widely recognized as significant obstacles to important and dependable food systems (Savary et al., 2019). Recent reports have demonstrated that plant diseases pose a significant threat to the food industry and to food security accounting for 10 to 40% crop losses annually on a global scale. Economic losses from plant diseases are estimated at $300B for major food crops, and diseases are associated with reduced food production, availability and accessibility as well as high food costs (Fletcher et al., 2006; Savary et al., 2019). Plants face different biotic stresses during their life cycle. For instance, a variety of diseases are caused by fungi, bacteria, protozoa, nematodes, viruses and phytoplasmas. These pathogens change favourable growing environments for plants into unfavourable conditions, particularly during susceptible growth stages. These cause significant yield losses both in greenhouses and under field conditions. Therefore, it is important to understand and utilize plants' innate immune systems to control plant pathogens to enable more sustainable agriculture (Brackin, Atkinson, Sturrock, & Rasmussen, 2017). Natural defense mechanisms involve a variety of signalling events and responses, which serve to combat intruding pathogens. The defense mechanism is categorized into constitutive and induced defense mechanisms. As the first line of defense, constitutive mechanisms utilize pre-formed chemicals and barriers such as ce...

Respiration, Rather Than Photosynthesis, Determines Rice Yield Loss Under Moderate High-Temperature Conditions

“…Among winter wheat cultivars widely grown in the US Great Plains, every 1°C increase in the nighttime temperature during the seed-fill period decreased the yield by 6% ( Hein et al, 2019 ). All these results were explained by the increased respiration at night ( Sadok and Jagadish, 2020 ; Impa et al, 2021 ).…”

“…Accordingly, no obvious difference in net photosynthetic rate (P N ) was shown among the temperature treatments of 28, 34, and 38°C in either rice genotypes, but the day respiration was significantly enhanced as the temperature increased ( Figure 1C ). It has been reported that the yield loss in rice and wheat by high night temperature is mainly ascribed to higher dark respiration, which increases the consumption of photoassimilates and thereby results in the reduction of nonstructural carbohydrates (NSC) in stem tissues ( Impa et al, 2021 ; Xu et al, 2021 ). Moreover, the enhanced dark respiration restrains source availability under the combined stress of high day-and-night temperatures, leading to a considerably more severe yield penalty due to carbon loss ( Xu et al, 2020 ).…”

Plant lipid metabolism in susceptible and tolerant soybean (Glycine max) cultivars in response to Phytophthora sojae colonization and infection

“…For instance, plant diseases are caused by infectious pathogens such as fungi, viruses, bacteria, and nematodes (Adigun et al 2020). These diseases lead to significant annual economic losses in maize, potato, wheat, rice, and soybean worldwide accounting for a 40% yield reduction (Adigun et al 2020, Fletcher et al 2006, Savary et al 2019). Globally, approximately $2B USD are lost annually due to soybean root and stem rot disease caused by the oomycete Phytophthora sojae (Dorrance et al 2003, Ranathunge et al 2008, Thomas et al 2007, Wrather et al 2001).…”

“…Induced defense mechanisms are triggered by pathogen ingress causing plants to synthesize compounds or enzymes as a result of pathogen detection. This may occur at the site of infection by processes like the oxidative burst or the hypersensitive response, or the production of chitinases, nitric oxide or phytoalexins (Adigun et al 2020). Furthermore, the response can be systemic in nature, producing pathogenesis-related proteins or the induction of systemic acquired resistance.…”

Plant lipid metabolism in response to Phytophthora sojae infection in susceptible and tolerant soybean cultivars

“…Lipid metabolites can also function as intracellular and extracellular signal mediators 18,20 . Plant lipids include glycerophospholipids (GPL), phytosterols (PST), sphingolipids (SGL), glycoglycerolipids (GGL) and glycerolipids (GL) 4,21,22 , and their metabolites are actively involved in plant defence responses against pathogen colonization 23,24 . They play important roles in the formation of the membrane interface between plant and microbial pathogen 23,24 .…”