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Plant Molecular Biology (2018) 97:201–214
https://doi.org/10.1007/s11103-018-0733-x
Molecular identification of GAPDHs in cassava highlights
the antagonism of MeGAPCs and MeATG8s in plant disease resistance
against cassava bacterial blight
Hongqiu Zeng
1
· Yanwei Xie
1
· Guoyin Liu
1
· Daozhe Lin
1
· Chaozu He
1
· Haitao Shi
1
Received: 15 September 2017 / Accepted: 18 April 2018 / Published online: 20 April 2018
© Springer Science+Business Media B.V., part of Springer Nature 2018
Abstract
Key message MeGAPCs were identified as negative regulators of plant disease resistance, and theinteraction of
MeGAPCs and MeATG8s was highlighted in plant defense response.
Abstract As an important enzyme of glycolysis metabolic pathway, glyceraldehyde-3-P dehydrogenase (GAPDH) plays
important roles in plant development, abiotic stress and immune responses. Cassava (Manihot esculenta) is most important
tropical crop and one of the major food crops, however, no information is available about GAPDH gene family in cassava. In
this study, 14 MeGAPDHs including 6 cytosol GAPDHs (MeGAPCs) were identified from cassava, and the transcripts of 14
MeGAPDHs in response to Xanthomonas axonopodis pv manihotis (Xam) indicated their possible involvement in immune
responses. Further investigation showed that MeGAPCs are negative regulators of disease resistance against Xam. Through
transient expression in Nicotiana benthamiana, we found that overexpression of MeGAPCs led to decreased disease resistance
against Xam. On the contrary, MeGAPCs-silenced cassava plants through virus-induced gene silencing (VIGS) conferred
improved disease resistance. Notably, MeGAPCs physically interacted with autophagy-related protein 8b (MeATG8b) and
MeATG8e and inhibited autophagic activity. Moreover, MeATG8b and MeATG8e negatively regulated the activities of NAD-
dependent MeGAPDHs, and are involved in MeGAPCs-mediated disease resistance. Taken together, this study highlights
the involvement of MeGAPCs in plant disease resistance, through interacting with MeATG8b and MeATG8e.
Keywords Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) · GAPC · Cassava (Manihot esculenta) · Protein–protein
interaction · Cassava bacterial blight · Autophagy
Introduction
Various environmental stresses including cold, drought,
salinity and pathogen infection seriously affect plant growth
and development, resulting in decreased food quality and
yield loss. In order to cope with harsh stress conditions,
plants have evolved and developed complex signaling net-
works to perceive and translate stress signaling pathways,
leading to protective responses (Hu et al. 2013; Shi et al.
2013). As a ubiquitous second messenger, reactive oxy-
gen species (ROS) especially hydrogen peroxide (H
2
O
2
)
is widely involved in multiple of stress signaling pathways
(Ape and Hirt 2004).
Glycolysis is an important metabolic pathway in car-
bohydrate metabolism almost present in all living organ-
isms (Plaxton 1996), glyceraldehyde-3-P dehydrogenase
(GAPDH) is a critical enzyme of glycolysis metabolic
pathway. There are four distinct isoforms of GAPDHs in
higher plants (Zhang et al. 2011). GAPA and GAPB are
phosphorylated and NADP-dependent GAPDH involved
in photosynthetic CO
2
fixation in chloroplasts; GAPCs are
phosphorylated and NAD-dependent GAPDH in the cytosol;
GAPCps are phosphorylated and NAD-dependent GAPDH
in nongreen plastids (Muñoz-Bertomeu et al. 2011; Petersen
et al. 2003); NP-GAPDH is cytosolic NADP-dependent and
nonphosphorylated GAPDH (Colell et al. 2007).
Electronic supplementary material The online version of this
article (https ://doi.org/10.1007/s1110 3-018-0733-x) contains
supplementary material, which is available to authorized users.
* Haitao Shi
haitaoshi@hainu.edu.cn
1
Hainan Key Laboratory for Sustainable Utilization
of Tropical Bioresources, Institute of Tropical Agriculture
and Forestry, Hainan University, Haikou 570228, China
@Phil_Robichaud
@deepthiw
@JoseServera