Investigation of low molecular weight heat shock proteins in Zea mays, L.

Date

1993-05

Journal Title

Journal ISSN

Volume Title

Publisher

Texas Tech University

Abstract

High temperatures may severely limit crop productivity in arid and semiarid regions. The limitation Is observed as failure to achieve full growth and development, thus reducing yield. Since plants are unable to escape from heat, adaptation is the only successful response. The acquisition of thermal tolerance Is a survival capacity following heat acclimation which has been correlated with the synthesis of heat shock proteins (HSPs) among plant species. However, no definitive evidence has concluded whether HSPs are necessary for determining genetic diversity and control of thermal tolerance. An approach to investigate the role of HSP genes in plant thermal tolerance is to explore molecular and genetic characteristics of the heat shock (HS) response.

The first objective of this research was to evaluate maize Inbreds Mo17 and 873 for genetic variation in cellular thermal tolerance, levels of HSP mRNA, and in vitro translatable HSP synthesis. Low molecular weight (LMW) HSP gene expression and organization were characterized by analysis of a cDNA encoding HSP17.2. The final objective was to examine HSP inheritance patterns using in vivo labelling in 873 X Mo17 Fi hybrids and F2 progeny.

Results indicate there are variations in acquired thermal tolerance and HSP synthesis, especially In genotype-specific LMW HSPs. A cDNA encoding LMW HSP17.2 shares nucleotide and amino acid similarities with other HSPs, is induced under natural HS temperatures, and is a member of a multi-gene family. HSP genes are expressed either dominantly, over-dominantly, or codominantly in the Fi hybrid, and segregate in the F2 progeny.

These results indicate that natural genetic diversity in cellular thermal tolerance may be linked to genotype-specific LMW HSPs and that several LMW HSPs are inherited according to Mendelian segregation patterns. This potentially provides a basis for improved heat tolerance in maize.

Description

Keywords

Heat shock proteins, Corn -- Effect of stress on, Corn -- Effect of temperature on

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