Pepper NAC-type transcription factor NAC2c balances the trade-off between growth and defense responses

Abstract

Plant responses to pathogen attacks and high-temperature stress (HTS) are distinct in nature but generally share several signaling components. How plants produce specific responses through these common signaling intermediates remains elusive. With the help of reverse-genetics approaches, we describe here the mechanism underlying trade-offs in pepper (Capsicum annuum) between growth, immunity, and thermotolerance. The NAC-type transcription factor CaNAC2c was induced by HTS and Ralstonia solanacearum infection (RSI). CaNAC2c-inhibited pepper growth, promoted immunity against RSI by activating jasmonate-mediated immunity and H2O2 accumulation, and promoted HTS responses by activating Heat shock factor A5 (CaHSFA5) transcription and blocking H2O2 accumulation. We show that CaNAC2c physically interacts with CaHSP70 and CaNAC029 in a context-specific manner. Upon HTS, CaNAC2c–CaHSP70 interaction in the nucleus protected CaNAC2c from degradation and resulted in the activation of thermotolerance by increasing CaNAC2c binding and transcriptional activation of its target promoters. CaNAC2c did not induce immunity-related genes under HTS, likely due to the degradation of CaNAC029 by the 26S proteasome. Upon RSI, CaNAC2c interacted with CaNAC029 in the nucleus and activated jasmonate-mediated immunity but was prevented from activating thermotolerance-related genes. In non-stressed plants, CaNAC2c was tethered outside the nucleus by interaction with CaHSP70, and thus was unable to activate either immunity or thermotolerance. Our results indicate that pepper growth, immunity, and thermotolerance are coordinately and tightly regulated by CaNAC2c via its inducible expression and differential interaction with CaHSP70 and CaNAC029.

The Laccase Gene Family Mediate Multi-Perspective Trade-Offs during Tea Plant (Camellia sinensis) Development and Defense Processes

“…In this study, herbivore attack enhanced the expression of most CsLACs in subclades IV, V and VI, but suppressed most genes in subclades I, II and III, which exhibited an opposite expression pattern. These results seems to obey the law that plants suffer limited resource reallocation to facilitate the prioritization of defense towards growth to survive during herbivore attack [4,45], and may account for the incompatibility between growth and defense programmes, known as the "growth-defense trade-off" phenomenon established upon plant-herbivore interactions [5,[46][47][48][49][50]. Altogether, our findings provide one CsLACsbased explanation for the growth-defense trade-off in tea plant at the molecular level.…”

Comparative Transcriptome Profiling Reveals Defense-Related Genes Against Ralstonia solanacearum Infection in Tobacco

“…In addition, the roles of cell wall proteins in defense against R. solanacearum in tomato have been discussed extensively ( Wydra and Beri, 2006 ; Diogo and Wydra, 2007 ; Dahal et al, 2010 ; Schacht et al, 2011 ). Moreover, several recent studies have identified genes related to plant defense against R. solanacearum , including StMKK1 in potato ( Chen et al, 2021 ), SlNAP1 and a bacterial effector protein RipAK in tomato ( Wang et al, 2020 ; Wang Y. et al, 2021 ), and CaNAC2c in pepper ( Cai et al, 2021 ).…”

CabHLH79 Acts Upstream of CaNAC035 to Regulate Cold Stress in Pepper

“…In order to the transient expression in pepper leaves, the recombination plasmid 35:CabHLH79-GFP and 35S:GFP were transformed into the Agrobacterium tumefaciens strain GV3101, the transient expression in pepper was followed by Cai et al [ 57 ]. Transcriptional levels of CabHLH79 in pepper leaves were detected by RT-qPCR.…”