ABC transporter genes ABC-C6 and ABC-G33 alter plant-microbe-parasite interactions in the rhizosphere

Kong

Plant Cell & Environment

et al. 2020

129

100

Plant-to-plant signalling is a key mediator of interactions among plant species. Plants can perceive and respond to chemical cues emitted from their neighbours, altering survival and performance, impacting plant coexistence and community assembly. An increasing number of studies indicate root exudates as key players in plant-to-plant signalling. Root exudates mediate root detection and behaviour, kin recognition, flowering and production, driving inter-and intra-specific facilitation in cropping systems and mixed-species plantations. Altered interactions may be attributed to the signalling components within root exudates. Root ethylene, strigolactones, jasmonic acid, (-)-loliolide and allantoin are signalling chemicals that convey information on local conditions in plant-plant interactions. These root-secreted signalling chemicals appear ubiquitous in plants and trigger a series of belowground responses inter-and intra-specifically, involving molecular events in biosynthesis, secretion and action. The secretion of root signals, mainly mediated by ATP-binding cassette transporters, is critical. Root-secreted signalling chemicals and their molecular mechanisms are rapidly revealing a multitude of fascinating plant-plant interactions. However, many root signals, particularly species-specific signals and their underlying mechanisms, remain to be uncovered due to methodological limitations and root-soil interactions. A thorough understanding of root-secreted chemical signals and their mechanisms will offer many ecological implications and potential applications for sustainable agriculture.

Section: Root‐secreted Chemical Signals and Their Molecular Mechanismsmentioning

confidence: 99%

Root exudate signals in plant–plant interactions

Kong

Plant Cell & Environment

et al. 2020

129

100

Plant Cell & Environment

“…In addition, passage of some lipophilic volatiles through hydrophilic cell walls is dependent on specific lipid transfer‐like proteins (DeBono et al, 2009). Finally, composition of semi‐volatile root exudates in tomato was altered after the genetic manipulation of ABC‐C6 and ABC‐G33 transporters (Cox et al, 2019). It remains an open question if specific transporters for plant terpenes also exist in plants, and if so, how they are participating in indirect plant defence.…”

Section: Discussionmentioning

confidence: 99%

Herbivore‐induced and constitutive volatiles are controlled by different oxylipin‐dependent mechanisms in rice

Mujiono

Tohi

Sobhy

et al. 2021

Despite the importance of volatile organic compounds (VOCs) for plants, control mechanisms for their basal and stress-induced biosynthesis and release remain unclear. We sampled and characterized headspace and internal leaf volatile pools in rice (Oryza sativa), after a simulated herbivory treatment, which triggers an endogenous jasmonate burst. Certain volatiles, such as linalool, were strongly upregulated by simulated herbivory stress. In contrast, other volatiles, such as β-caryophyllene, were constitutively emitted and fluctuated according to time of day. Transcripts of the linalool synthase gene transiently increased 1-3 h after exposure of rice to simulated herbivory, whereas transcripts of caryophyllene synthase peaked independently at dawn. Unexpectedly, although emission and accumulation patterns of rice inducible and constitutive VOCs were substantially different, both groups of volatiles were compromised in jasmonate-deficient hebiba mutants, which lack the allene oxide cyclase (AOC) gene. This suggests that rice employs at least two distinct oxylipindependent mechanisms downstream of AOC to control production of constitutive and herbivore-induced volatiles. Levels of the JA precursor, 12-oxo-phytodienoic acid (OPDA), were correlated with constitutive volatile levels suggesting that OPDA or its derivatives could be involved in control of volatile emission in rice.

“…The PCR products were digested with Eco RI and Xho I and ligated to the tobacco rattle virus RNA 2 vector (TRV2) for the transformation of A. tumefaciens strain GV3101. VIGS assays were performed, as previously described, by the co-infiltration of leaves of three-week-old N. benthamiana plants (Lange et al , 2013; Velasquez et al , 2009) or 10-days-old tomato plants (Cox et al , 2019) with agrobacterial strains containing the RNA 1 vector (TRV1) and TRV2. Tomato plants were incubated at 16°C for four weeks.…”

Section: Methodsmentioning

confidence: 99%

Silencing SmD1 in Solanaceae alters susceptibility to root-knot nematodes

Mejias

Chen

Truong

et al. 2020

Preprint

SummaryRoot-knot nematodes (RKNs) are among the most damaging pests of agricultural crops. Indeed, Meloidogyne is an extremely polyphagous genus of nematodes that can infect thousands of plant species. A few genes for resistance (R-genes) to RKNs suitable for use in crop breeding have been identified, and new virulent strains and species of nematode emerge rendering these R-genes ineffective. Effective parasitism is dependent on the secretion, by the RKN, of effectors targeting plant functions, which mediate the reprogramming of root cells into specialised feeding cells. These cells, the giant cells, are essential for RKN development and reproduction. The EFFECTOR 18 protein (EFF18) from M. incognita interacts with the spliceosomal protein SmD1 in Arabidopsis, disrupting its function in alternative splicing regulation and modulating the giant cell transcriptome. We show here that EFF18 is a conserved RKN-specific effector. We also show here that EFF18 effectors also target SmD1 in Nicotiana benthamiana and Solanum lycopersicum. The alteration of SmD1 expression by virus-induced gene silencing (VIGS) in Solanaceae affects giant cell formation and nematode development. Thus, SmD1 is a susceptibility gene and a promising target for the development of broad resistance, especially in Solanaceae, for the control of Meloidogyne spp.