The molecular chaperone binding protein BiP prevents leaf dehydration-induced cellular homeostasis disruption.
PLoS One
; 9(1): e86661, 2014.
Article
em En
| MEDLINE
| ID: mdl-24489761
ABSTRACT
BiP overexpression improves leaf water relations during droughts and delays drought-induced leaf senescence. However, whether BiP controls cellular homeostasis under drought conditions or simply delays dehydration-induced leaf senescence as the primary cause for water stress tolerance remains to be determined. To address this issue, we examined the drought-induced transcriptomes of BiP-overexpressing lines and wild-type (WT) lines under similar leaf water potential (ψw) values. In the WT leaves, a ψw reduction of -1.0 resulted in 1339 up-regulated and 2710 down-regulated genes; in the BiP-overexpressing line 35SBiP-4, only 334 and 420 genes were induced and repressed, respectively, at a similar leaf ψwâ=â-1.0 MPa. This level of leaf dehydration was low enough to induce a repertory of typical drought-responsive genes in WT leaves but not in 35SBiP-4 dehydrated leaves. The responders included hormone-related genes, functional and regulatory genes involved in drought protection and senescence-associated genes. The number of differentially expressed genes in the 35SBiP-4 line approached the wild type number at a leaf ψwâ=â-1.6 MPa. However, N-rich protein (NRP)- mediated cell death signaling genes and unfolded protein response (UPR) genes were induced to a much lower extent in the 35SBiP-4 line than in the WT even at ψwâ=â-1.6 MPa. The heatmaps for UPR, ERAD (ER-associated degradation protein system), drought-responsive and cell death-associated genes revealed that the leaf transcriptome of 35SBiP-4 at ψwâ=â-1.0 MPa clustered together with the transcriptome of well-watered leaves and they diverged considerably from the drought-induced transcriptome of the WT (ψwâ=â-1.0, -1.7 and -2.0 MPa) and 35SBiP-4 leaves at ψwâ=â-1.6 MPa. Taken together, our data revealed that BiP-overexpressing lines requires a much higher level of stress (ψwâ=â-1.6 MPa) to respond to drought than that of WT (ψwâ=â-1.0). Therefore, BiP overexpression maintains cellular homeostasis under water stress conditions and thus ameliorates endogenous osmotic stress.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Plantas
/
Glycine max
/
Folhas de Planta
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Regulação da Expressão Gênica de Plantas
/
Proteínas de Choque Térmico
/
Homeostase
Idioma:
En
Revista:
PLoS One
Assunto da revista:
CIENCIA
/
MEDICINA
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Brasil