A gene encoding a protein modified by the phytohormone indoleacetic acid

Abstract

We show that the expression of an indole-3-acetic acid (IAA)-modified protein from bean seed, IAP1, is correlated to the developmental period of rapid growth during seed development. Moreover, this protein undergoes rapid degradation during germination. The gene for IAP1, the most abundant protein covalently modified by IAA (iap1, GenBank accession no. AF293023) was isolated and cloned from bush bean (Phaseolus vulgaris) seeds. The 957-bp sequence encodes a 35-kDa polypeptide. IAA-modified proteins represent a distinct class of conjugated phytohormones and appear in bean to be the major form of auxin in seeds. IAA proteins also are found at other stages of development in bean plants. Our immunological and analytical data suggest that auxin modification of a small class of proteins may be a feature common to many plants.

A Novel Auxin Conjugate Hydrolase from Wheat with Substrate Specificity for Longer Side-Chain Auxin Amide Conjugates

“…One strategy to regulate IAA-ester conjugates occurs in maize, where it was demonstrated that the enzyme catalyzing the conjugation of IAA to myoinositol was also able to catalyze the hydrolysis of the IAA-ester conjugate (Kowalczyk et al, 2003). Amide-type auxin conjugates, including acyl peptides and proteins (Walz et al 2002), were not found in wheat seeds (Bandurski and Schulze, 1977), but their occurrence in vegetative tissues cannot be ruled out.…”

“…These two types of conjugates appear to be found at varying concentrations in the diverse tissues of angiosperms (Domagalski et al, 1987). On average, 95% of all IAA in a plant is conjugated into these storage forms (Cohen and Bandurski, 1982;Bandurski et al, 1995;Campanella et al, 1996;Walz et al, 2002).There have been a variety of amide conjugates found in the plants studied to date. IAA-Asp has been identified as a natural conjugate in Scots pine (Pinus sylvestris; Andersson and Sandberg, 1982) and, together with IAA-Glu, in cucumber (Sonner and Purves, 1985) and soybean (Cohen, 1982).…”

“…IAA-Ala has been detected in Picea abies Karst (Ö stin et al, 1992). Additionally, IAA-Ala, IAA-Asp, IAA-Leu, and IAA-Glu have been detected in Arabidopsis L. Heynh (Tam et al, 2000;Kowalczyk and Sandberg, 2001), although recent data suggest that IAA peptides may account for the majority of amide conjugates in this and other plant species (Walz et al, 2002;Park et al, 2003).Common IAA-ester conjugates include IAAmyoinositol glycosides, IAA-myoinositol, and IAAGlc (Bandurski et al, 1969;Kopcewicz et al, 1974;Bandurski and Schulze, 1977;Domagalski et al, 1987). These ester conjugates have been identified in many species over the last 60 years (Bandurski et al, 1969;Slovin et al, 1999).…”

“…IAA-Ala has been detected in Picea abies Karst (Ö stin et al, 1992). Additionally, IAA-Ala, IAA-Asp, IAA-Leu, and IAA-Glu have been detected in Arabidopsis L. Heynh (Tam et al, 2000;Kowalczyk and Sandberg, 2001), although recent data suggest that IAA peptides may account for the majority of amide conjugates in this and other plant species (Walz et al, 2002;Park et al, 2003).…”

“…These two types of conjugates appear to be found at varying concentrations in the diverse tissues of angiosperms (Domagalski et al, 1987). On average, 95% of all IAA in a plant is conjugated into these storage forms (Cohen and Bandurski, 1982;Bandurski et al, 1995;Campanella et al, 1996;Walz et al, 2002).…”