A necessary considering factor for breeding:growth-defense tradeoff in plants

Crop diseases cause enormous yield losses and threaten global food security.Deployment of resistant cultivars can effectively control the disease and to minimize crop losses.However,high level of genetic immunity to disease was often accompanied by an undesired reduction in crop growth and yield.Recently,literatures have been rapidly emerged in understanding the mechanism of disease resistance and development genes in crop plants.To determine how and why the costs and the likely benefit of resistance genes caused in crop varieties,we re-summarized the present knowledge about the crosstalk between plant development and disease resistance caused by those genes that function as plasma membrane residents,MAPK cassette,nuclear envelope(NE)channels components and pleiotropic regulators.Considering the growth-defense tradeoffs on the basis of current advances,finally,we try to understand and suggest that a reasonable balancing strategies based on the interplay between immunity with growth should be considered to enhance immunity capacity without yield penalty in future crop breeding.

DELLA and EDS1 Form a Feedback Regulatory Module to Fine-Tune Plant Growth-Defense Tradeoff in Arabidopsis

Plants maintain a dynamic balance between growth and defense,and optimize allocation of resources for survival under constant pathogen infections.However,the underlying molecular regulatory mechanisms,especially in response to biotrophic bacterial infection,remain elusive.Here,we demonstrate that DELLA proteins and EDS1,an essential resistance regulator,form a central module modulating plant growth-defense tradeoffs via direct interaction.When infected by Pst DC3000,EDS1 rapidly promotes salicylic acid(SA)biosynthesis and resistance-related gene expression to prime defense response,while pathogen infection stabilizes DELLA proteins RGA and RGL3 to restrict growth in a partially EDS1-dependent manner,which facilitates plants to develop resistance to pathogens.However,the increasingly accumulated DELLAs interact with EDS1 to suppress SA overproduction and excessive resistance response.Taken together,our findings reveal a DELLA-EDS1-mediated feedback regulatory loop by which plants maintain the subtle balance between growth and defense to avoid excessive growth or defense in response to constant biotrophic pathogen attack.

Expanding Roles of PIFs in Signal Integration from Multiple Processes

PHYTOCHROME-INTERACTING FACTORs （PIFs） are members of the basic helix-loop-helix （bHLH） family of transcription factors in Arabidopsis. Since their discovery in phytochrome-mediated light signaling pathways, recent studies have unraveled new functions of PIFs in integrating multiple signaling pathways not only through their role as transcription factors directly targeting gene expression but also by interacting with diverse groups of factors to optimize plant growth and development. These include endogenous （e.g., hormonal） as well as abiotic （light, circadian, and elevated temperature） and biotic （defense responses） pathways. PIFs interact with key factors in each of these pathways and tailor the outcome of the signal integration among these pathways. This review discusses the roles of PIFs as pivotal signal integrators in regulating plant growth and development.

Control of Plant Growth and Defense by Photoreceptors:From Mechanisms to Opportunities in Agriculture

Plants detect and respond to the proximity of competitors using light signals perceived by photoreceptor proteins.A low ratio of red to far-red radiation(R:FR ratio)is a key signal of competition that is sensed by the photoreceptor phytochrome B(phyB).Low R:FR ratios increase the synthesis of growth-related hormones,including auxin and gibberellins,promoting stem elongation and other shade-avoidance responses.Other photoreceptors that help plants to optimize their developmental configuration and resource allocation patterns in the canopy include blue light photoreceptors,such as cryptochromes and phototropins,and UV receptors,such as UVR8.All photoreceptors act by directly or indirectly controlling the activity of two major regulatory nodes for growth and development:the COP1/SPA ubiquitin E3 ligase complex and the PIF transcription factors.phyB is also an important modulator of hormonal pathways that regulate plant defense against herbivores and pathogens,including the jasmonic acid signaling pathway,In this Perspective,we discuss recent advances on the studies of the mechanisms that link photoreceptors with growth and defense.Understanding these mechanisms is important to provide a functional platform for breeding programs aimed at improving plant productivity,stress tolerance,and crop health in species of agronomic interest,and to manipulate the light environments in protected agriculture.

Phosphorylation of a wheat aquaporin at two sites enhances both plant growth and defense

Eukaryotic aquaporins share the characteristic of functional multiplicity in transporting distinct substrates and regulating various processes,but the underlying molecular basis for this is largely unknown.Here,we report that the wheat(Triticum aestivum)aquaporin TaPIP2;10 undergoes phosphorylation to promote photosynthesis and productivity and to confer innate immunity against pathogens and a generalist aphid pest.In response to elevated atmospheric CO_(2)concentrations,TaPIP2;10 is phosphorylated at the serine residue S280 and thereafter transports CO_(2)into wheat cells,resulting in enhanced photosynthesis and increased grain yield.In response to apoplastic H_(2)O_(2) induced by pathogen or insect attacks,TaPIP2;10 is phosphorylated at S121 and this phosphorylated form transports H_(2)O_(2) into the cytoplasm,where H_(2)O_(2)intensifies host defenses,restricting further attacks.Wheat resistance and grain yield could be simultaneously increased by TaPIP2;10 overexpression or by expressing a TaPIP2;10 phosphomimic with aspartic acid substitutions at S121 and S280,thereby improving both crop productivity and immunity.