An Updated Review on the Modulation of Carbon Partitioning and Allocation in Arbuscular Mycorrhizal Plants

Arbuscular mycorrhizal fungi (AMF) are obligate biotrophs that supply mineral nutrients to the host plant in exchange for carbon derived from photosynthesis. Sucrose is the end-product of photosynthesis and the main compound used by plants to translocate photosynthates to non-photosynthetic tissues. AMF alter carbon distribution in plants by modifying the expression and activity of key enzymes of sucrose biosynthesis, transport, and/or catabolism. Since sucrose is essential for the maintenance of all metabolic and physiological processes, the modifications addressed by AMF can significantly affect plant development and stress responses. AMF also modulate plant lipid biosynthesis to acquire storage reserves, generate biomass, and fulfill its life cycle. In this review we address the most relevant aspects of the influence of AMF on sucrose and lipid metabolism in plants, including its effects on sucrose biosynthesis both in photosynthetic and heterotrophic tissues, and the influence of sucrose on lipid biosynthesis in the context of the symbiosis. We present a hypothetical model of carbon partitioning between plants and AMF in which the coordinated action of sucrose biosynthesis, transport, and catabolism plays a role in the generation of hexose gradients to supply carbon to AMF, and to control the amount of carbon assigned to the fungus.

In Vitro Growth Conditions Boost Plant Lipid Remodelling and Influence Their Composition

Acyl-lipids are vital components for all life functions of plants. They are widely studied using often in vitro conditions to determine inter alia the impact of genetic modifications and the description of biochemical and physiological functions of enzymes responsible for acyl-lipid metabolism. What is currently lacking is knowledge of if these results also hold in real environments—in in vivo conditions. Our study focused on the comparative analysis of both in vitro and in vivo growth conditions and their impact on the acyl-lipid metabolism of Camelina sativa leaves. The results indicate that in vitro conditions significantly decreased the lipid contents and influenced their composition. In in vitro conditions, galactolipid and trienoic acid (16:3 and 18:3) contents significantly declined, indicating the impairment of the prokaryotic pathway. Discrepancies also exist in the case of acyl-CoA:lysophospholipid acyltransferases (LPLATs). Their activity increased about 2–7 times in in vitro conditions compared to in vivo. In vitro conditions also substantially changed LPLATs’ preferences towards acyl-CoA. Additionally, the acyl editing process was three times more efficient in in vitro leaves. The provided evidence suggests that the results of acyl-lipid research from in vitro conditions may not completely reflect and be directly applicable in real growth environments.

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

Soybean is one of the most cultivated crops globally and a staple food for much of the world's population. The annual global crop losses due to infection by the Phytophthora sojae are currently estimated at approximately $2B USD, yet we have limited understanding of the role of lipid metabolism in the adaptative strategies used to limit infection and crop loss. We employed a multi-modal lipidomics approach to investigate how soybean cultivars remodel their lipid metabolism to successfully limit infection by Phytophthora sojae. Both the tolerant and susceptible soybean cultivars showed alterations in lipid metabolism in response to Phytophthora sojae infection. Relative to non-inoculated controls, induced accumulation of stigmasterol was observed in the susceptible cultivar whereas, induced accumulation of phospholipids and glycerolipids occurred in tolerant soybean cultivar. We have generated a comprehensive metabolic map of susceptible and tolerant soybean root and stem lipid metabolism to identify lipid modulators of host immune or tolerance response to Phytophthora sojae infection and identified potential pathways and unique lipid biomarkers like TG(15:0/22:0/22:5), TG(10:0/10:0/10:0), TG(10:0/10:0/14:0), DG(18:3/18:3), DG(16:0/18:3) and DG(24:0/18:2) as possible targets for the development of future plant protection solutions.

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

Soybean is one of the most cultivated crops globally and a staple food for much of the world's population. The annual global crop losses due to infection by the Phytophthora sojae are currently estimated at approximately $2B USD, yet we have limited understanding of the role of lipid metabolism in the adaptative strategies used to limit infection and crop loss. We employed a multi-modal lipidomics approach to investigate how soybean cultivars remodel their lipid metabolism to successfully limit infection by Phytophthora sojae. Both the tolerant and susceptible soybean cultivars showed alterations in lipid metabolism in response to Phytophthora sojae infection. Relative to non-inoculated controls, induced accumulation of stigmasterol was observed in the susceptible cultivar whereas, induced accumulation of phospholipids and glycerolipids occurred in tolerant soybean cultivar. We have generated a comprehensive metabolic map of susceptible and tolerant soybean root and stem lipid metabolism to identify lipid modulators of host immune or tolerance response to Phytophthora sojae infection and identified potential pathways and unique lipid biomarkers like TG(15:0/22:0/22:5), TG(10:0/10:0/10:0), TG(10:0/10:0/14:0), DG(18:3/18:3), DG(16:0/18:3) and DG(24:0/18:2) as possible targets for the development of future plant protection solutions.

Lipid metabolism and accumulation in oilseed crops

Triacylglycerols (TAGs) serve as the most important storage form of energy and carbon in eukaryotic cells and thus are one of the fundamental macronutrients for animal and human diet. They are also used as a major feedstock for diverse industrial and energetic sectors due to their high energy density. Oilseed crops represent the most valuable source of TAGs and major world sources of edible oils. Originally, oilseeds of various species were used as a model to decipher plant lipid synthesis pathways. Given the continuous progress in research on plant lipid metabolism, here we provide an overview and update on the current state of knowledge related mainly to storage lipids in oilseeds. Moreover, we present the latest evidences on the molecular networks governing metabolism not only of TAGs but also of other seed lipids, like wax esters, sterols and sphingolipids. Finally, this review also provides a framework for understanding the complex lipid web existing in oilseeds.

The state of the art in plant lipidomics

In this review, we provide a critical appraisal of the key developments, current state and future trends in liquid-chromatography–mass spectrometry-based workflows for plant lipid analysis.