Overexpression of stress-inducible OsBURP16, the β subunit of polygalacturonase 1, decreases pectin content and cell adhesion and increases abiotic stress sensitivity in rice.
Polygalacturonase (PG), one of the hydrolases responsible for cell wall pectin degradation, is involved in organ consenescence and biotic stress in plants. PG1 is composed of a catalytic subunit, PG2, and a non-catalytic PG1β subunit. OsBURP16 belongs to the PG1β-like subfamily of BURP-family genes and encodes one putative PG1β subunit precursor in rice (Oryza sativa L.). Transcription of OsBURP16 is induced by cold, salinity and drought stresses, as well as by abscisic acid (ABA) treatment. Analysis of plant survival rates, relative ion leakage rates, accumulation levels of H2 O2 and water loss rates of leaves showed that overexpression of OsBURP16 enhanced sensitivity to cold, salinity and drought stresses compared with controls. Young leaves of Ubi::OsBURP16 transgenic plants showed reduced cell adhesion and increased cuticular transpiration rate. Mechanical strength measurement of Ubi::OsBURP16 plants showed that reduced force was required to break leaves as compared with wild type. Transgenic rice showed enhanced PG activity and reduced pectin content. All these results suggested that overexpression of OsBURP16 caused pectin degradation and affected cell wall integrity as well as transpiration rate, which decreased tolerance to abiotic stresses.
Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China; Graduate University of the Chinese Academy of Sciences, Beijing, 100049, China.
Huanhuan
H
Liu
Yan
Y
Ma
Na
N
Chen
Siyi
S
Guo
Huili
H
Liu
Xiaoyu
X
Guo
Kang
K
Chong
Yunyuan
Y
Xu
D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics; D000595:Amino Acid Sequence; D002448:Cell Adhesion / Q000187:drug effects; D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism; D003080:Cold Temperature; D055864:Droughts; D004790:Enzyme Induction / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D008969:Molecular Sequence Data; D012275:Oryza / Q000166:cytology* / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D010368:Pectins / Q000378:metabolism*; D010641:Phenotype; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018526:Plant Transpiration / Q000187:drug effects; D030821:Plants, Genetically Modified; D011096:Polygalacturonase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D014574:Uronic Acids / Q000378:metabolism
D010940:Plant Proteins; D021122:Protein Subunits; D014574:Uronic Acids; D012965:Sodium Chloride; D010368:Pectins; D011096:Polygalacturonase
abiotic stress; cell adhesion; pectin; polygalacturonase