Maize HSP101 plays important roles in both induced and basal thermotolerance and primary root growth.
HSP101 belongs to the ClpB protein subfamily whose members promote the renaturation of protein aggregates and are essential for the induction of thermotolerance. We found that maize HSP101 accumulated in mature kernels in the absence of heat stress. At optimal temperatures, HSP101 disappeared within the first 3 days after imbibition, although its levels increased in response to heat shock. In embryonic cells, HSP101 concentrated in the nucleus and in some nucleoli. Hsp101 maps near the umc132 and npi280 markers on chromosome 6. Five maize hsp101-m-::Mu1 alleles were isolated. Mutants were null for HSP101 and defective in both induced and basal thermotolerance. Moreover, during the first 3 days after imbibition, primary roots grew faster in the mutants at optimal temperature. Thus, HSP101 is a nucleus-localized protein that, in addition to its role in thermotolerance, negatively influences the growth rate of the primary root. HSP101 is dispensable for proper embryo and whole plant development in the absence of heat stress.
Department of Plant Molecular Biology, Institute of Biotechnology, National Autonomous University of Mexico, 62250 Cuernavaca, Morelos, Mexico. jorge@ibt.unam.mx
Jorge
J
Nieto-Sotelo
Luz María
LM
Martínez
Georgina
G
Ponce
Gladys I
GI
Cassab
Alejandro
A
Alagón
Robert B
RB
Meeley
Jean-Marcel
JM
Ribaut
Runying
R
Yang
D000064:Acclimatization / Q000235:genetics / Q000502:physiology; D001483:Base Sequence; D002467:Cell Nucleus / Q000378:metabolism; D002874:Chromosome Mapping; D018506:Gene Expression Regulation, Plant; D018525:Germination / Q000235:genetics; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006358:Hot Temperature; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development*; D012639:Seeds / Q000235:genetics / Q000254:growth & development; D003313:Zea mays / Q000737:chemistry / Q000235:genetics / Q000254:growth & development*
D006360:Heat-Shock Proteins; D010940:Plant Proteins