TY - JOUR
T1 - Uncovering DELLA-independent gibberellin responses by characterizing new tomato procera mutants
AU - Livne, Sivan
AU - Lor, Vai S.
AU - Nir, Ido
AU - Eliaz, Natanella
AU - Aharoni, Asaph
AU - Olszewski, Neil E.
AU - Eshed, Yuval
AU - Weiss, David
N1 - Publisher Copyright:
© 2015 American Society of Plant Biologists. All rights reserved.
PY - 2015/6/1
Y1 - 2015/6/1
N2 - Gibberellin (GA) regulates plant development primarily by triggering the degradation/deactivation of the DELLA proteins. However, it remains unclear whether all GA responses are regulated by DELLAs. Tomato (Solanum lycopersicum) has a single DELLA gene named PROCERA (PRO), and its recessivepro allele exhibits constitutive GA activity but retains responsiveness to externalGA. In the loss-of-function mutant proΔGRAS, all examined GA developmental responses were considerably enhanced relative to pro and a defect in seed desiccation tolerance was uncovered. As pro, but not proΔGRAS, elongation was promoted by GA treatment, pro may retain residual DELLA activity. In agreement with homeostatic feedback regulation of the GA biosynthetic pathway, we found that GA20oxidase1 expression was suppressed in proΔGRAS and was not affected by exogenous GA3. In contrast, expression of GA2oxidase4 was not affected by the elevated GA signaling in proΔGRAS but was strongly induced by exogenous GA3. Since a similar response was found in Arabidopsis thaliana plants with impaired activity of all five DELLA genes, we suggest that homeostatic GAresponses are regulated by both DELLA-dependent and -independent pathways. Transcriptome analysis of GA-treated proΔGRAS leaves suggests that 5% of allGA-regulated genes in tomato are DELLA independent.
AB - Gibberellin (GA) regulates plant development primarily by triggering the degradation/deactivation of the DELLA proteins. However, it remains unclear whether all GA responses are regulated by DELLAs. Tomato (Solanum lycopersicum) has a single DELLA gene named PROCERA (PRO), and its recessivepro allele exhibits constitutive GA activity but retains responsiveness to externalGA. In the loss-of-function mutant proΔGRAS, all examined GA developmental responses were considerably enhanced relative to pro and a defect in seed desiccation tolerance was uncovered. As pro, but not proΔGRAS, elongation was promoted by GA treatment, pro may retain residual DELLA activity. In agreement with homeostatic feedback regulation of the GA biosynthetic pathway, we found that GA20oxidase1 expression was suppressed in proΔGRAS and was not affected by exogenous GA3. In contrast, expression of GA2oxidase4 was not affected by the elevated GA signaling in proΔGRAS but was strongly induced by exogenous GA3. Since a similar response was found in Arabidopsis thaliana plants with impaired activity of all five DELLA genes, we suggest that homeostatic GAresponses are regulated by both DELLA-dependent and -independent pathways. Transcriptome analysis of GA-treated proΔGRAS leaves suggests that 5% of allGA-regulated genes in tomato are DELLA independent.
UR - http://www.scopus.com/inward/record.url?scp=84936929584&partnerID=8YFLogxK
U2 - 10.1105/tpc.114.132795
DO - 10.1105/tpc.114.132795
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C2 - 26036254
AN - SCOPUS:84936929584
SN - 1040-4651
VL - 27
SP - 1579
EP - 1594
JO - Plant Cell
JF - Plant Cell
IS - 6
ER -