Transport and metabolism of indole-3-butyric acid in cuttings of Leucadendron discolor

Epstein, Ephraim; Ackerman, A.

doi:10.1007/bf00144577

Cited by 13 publications

(10 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The formation of the large amount of ester-linked IBA is consistent with what was found previously, and the major conjugate is most likely IBA-Glc (Epstein and Ackerman, 1993;Baraldi et al, 1995). On the other hand, the total amount of free and conjugated [ Tognetti et al (2010) found that the gene encoding the IBA-Glc-conjugating enzyme (UGT74E2) was rapidly and strongly induced by oxidative stress and the level of IBA-Glc was dramatically increased under stress conditions, it is possible that the IBA-Glc-conjugating activity was significantly induced at the cut surface of the hypocotyl and that the formation of IBA-Glc conjugates led to more IBA taken up into the plant tissue.…”

Section: Discussionsupporting

confidence: 90%

Transport of Indole-3-Butyric Acid and Indole-3-Acetic Acid in Arabidopsis Hypocotyls Using Stable Isotope Labeling

et al. 2012

View full text Add to dashboard Cite

The polar transport of the natural auxins indole-3-butyric acid (IBA) and indole-3-acetic acid (IAA) has been described in Arabidopsis (Arabidopsis thaliana) hypocotyls using radioactive tracers. Because radioactive assays alone cannot distinguish IBA from its metabolites, the detected transport from applied [ ]IAA was found in the basal end. Our results demonstrate that the polar transport of IBA is much lower than IAA in Arabidopsis hypocotyls, and the transport mechanism is distinct from IAA transport. These experiments also establish a method for quantifying the movement of small molecules in plants using stable isotope labeling.Indole-3-acetic acid (IAA), the most abundant form of the plant hormone auxin, is critical for plant growth and development. IAA levels are regulated in plants by multiple means, including biosynthesis of IAA through both Trp-dependent and Trp-independent pathways, conjugation of IAA via ester or amide bonds that can be hydrolyzed to release free IAA, polar transport of IAA over long distances, and degradation of IAA (for review, see Woodward and Bartel, 2005;Seidel et al.,

show abstract

Section: Discussionsupporting

confidence: 90%

Transport of Indole-3-Butyric Acid and Indole-3-Acetic Acid in Arabidopsis Hypocotyls Using Stable Isotope Labeling

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Additional studies have examined the distribution of radiolabeled IBA after application of a rooting solution to the base of explants. In most cases, however, these studies were not designed to distinguish between movement of auxin in the plant's vascular system and polar auxin transport (for example, see Epstein and Lavee, 1984;Wiesman et al, 1988;van der Krieken et al, 1992;Epstein and Ackerman, 1993). In one notable exception, IBA polar transport was examined in excised citrus leaf midribs and found to be twice as high in the basipetal direction as in the acropetal direction (Epstein and Sagee, 1992).…”

mentioning

confidence: 97%

Transport of the Two Natural Auxins, Indole-3-Butyric Acid and Indole-3-Acetic Acid, in Arabidopsis

et al. 2003

View full text Add to dashboard Cite

Polar transport of the natural auxin indole-3-acetic acid (IAA) is important in a number of plant developmental processes. However, few studies have investigated the polar transport of other endogenous auxins, such as indole-3-butyric acid (IBA), in Arabidopsis. This study details the similarities and differences between IBA and IAA transport in several tissues of Arabidopsis. In the inflorescence axis, no significant IBA movement was detected, whereas IAA is transported in a basipetal direction from the meristem tip. In young seedlings, both IBA and IAA were transported only in a basipetal direction in the hypocotyl. In roots, both auxins moved in two distinct polarities and in specific tissues. The kinetics of IBA and IAA transport appear similar, with transport rates of 8 to 10 mm per hour. In addition, IBA transport, like IAA transport, is saturable at high concentrations of auxin, suggesting that IBA transport is protein mediated. Interestingly, IAA efflux inhibitors and mutations in genes encoding putative IAA transport proteins reduce IAA transport but do not alter IBA movement, suggesting that different auxin transport protein complexes are likely to mediate IBA and IAA transport. Finally, the physiological effects of IBA and IAA on hypocotyl elongation under several light conditions were examined and analyzed in the context of the differences in IBA and IAA transport. Together, these results present a detailed picture of IBA transport and provide the basis for a better understanding of the transport of these two endogenous auxins.

show abstract

“…This theory is supported by reports on increased levels of free auxin in the bases of cuttings prior to rooting (Brunner 1978, Moncousin et ai. 1989, Liu and Reid 1992, Epstein and Ackerman 1993 used the conjugate inhibitor 2,6-dihydroxyacetophenone (DHAP, Lee and Starratt 1986) in order to increase the level of free auxin in cuttings of the difficult-to-root olive cv, Uovo di Piccone. Significantly more cuttings rooted following treatment with 2 mM DHAP and 0.8% IBA than with 0.8% IBA alone (30% vs 15%, respectively).…”

Section: Iba Conjugatesmentioning

confidence: 99%

“…However, when they used stem segments from cuttings which were pretreated with 10 mg ml ' of IBA for 24 h they noticed an increase in the translocation of IAA. In an experiment with L, i/(.yco/or (Epstein and Ackerman 1993), cuttings of easyand difficult-to-root cultivars were incubated with labeled IBA. The major difference in the transport between the two cultivars was that in the difficult-to-root cultivar the label in the leaves was almost a constant 10% of the total uptake, while in the easy-to-root leaves the value increased after 2 weeks to 30% and after 3 weeks to 45% , with a final level of 357o after 4 weeks (the same as in the shoot).…”

Section: Uptake and Transport Of Ibamentioning

confidence: 99%

Indole-3-butyric acid in plants: occurrence, synthesis, metabolism and transport

Epstein¹,

Ludwig²

1993

Physiol Plant

View full text Add to dashboard Cite

Miiller, J. 1993. Indole-3-butyric acid in plants: occurrence, synthesis, metabolism and transport. -Physiol. Plant. 88: 382-389.Indole-3-butyric acid (IBA) was recently identified by GC/MS analysis as an endogenous constituent of various plants. Plant tissues contained 9 ng g~ fresh weight of free IBA and 37 ngg 'fresh weight of total IBA, compared to 26 ngg ' and 52 ngg ' fresh weight of free and total indole-3-acetic acid (lAA), respectively. IBA level was found to increase during plant development, but never reached the level of lAA. It is generally assumed that the greater ability of IBA as compared with lAA to promote rooting is due to its relatively higher stability. Indeed, the concentrations of lAA and IBA in autodaved medium were reduced by 40% and 20%, respectively, compared with filter sterilized controls. In liquid medium. IAA was more sensitive than IBA to non-biological degradation. However, in all plant tissues tested, both auxins were found to be metabolized rapidly and conjugated at the same rate with amino acids or sugar. Studies of auxin transport showed that IAA was transported faster than IBA. The velocities of some of the auxins tested were 7.5 mm h' for IAA, 6.7 mm h ' for naphthaleneacetic acid (NAA) and only 3.2 mm h ' for IBA. Like IAA, IBA was transported predominantly in a basipetal direction (polar transport). After application of 'H-IBA to cuttings of various plants, most of the label remained in the bases of the cuttings. Easy-to-root cultivars were found to absorb more of the auxin and transport more of it to the leaves. It has been postulated that easy-to-root, as opposed to the difficult-to-rool cultivars, have the ability to hydrolyze auxin conjugates at the appropriate time to release free auxin which may promote root initiation. This theory is supported by reports on increased levels of free auxin in the bases of cuttings prior to rooting. The auxin conjugate probably acts as a 'slow-release' hormone in the tissues. Easy-to-root cultivars were also able to convert IBA to IAA which accumulated in the cutting bases prior to rooting. IAA conjugates, but not IBA conjugates, were subject lo oxidation, and thus deactivation. The efficiency of the two auxins in root induction therefore seems to depend on the stability of their conjugates. The higher rooting promotion of IBA was also ascribed to the fact that its level remained elevated longer than that of IAA, even though IBA was metabolized in the tissue. IAA was converted to IBA by seedlings of corn and Arabidopsis. The K^ value for IBA formation was low (approximately 20 \iM), indicating high affinity for the substrate. That means that small amounts of IAA (only a fraction of the total IAA in the plant tissues) can be converted to IBA. It was suggested that IBA is formed by the acetylation of IAA with acetyl-CoA in the carboxyi position via a biosynthetic pathway analogous to the primary steps of fatty acid biosynthesis, where acetyl moieties are transferred to an acceptor molecule. Incubation of the soluble enzyme fraction from ...

show abstract

Transport and metabolism of indole-3-butyric acid in cuttings of Leucadendron discolor

Cited by 13 publications

References 12 publications

Transport of Indole-3-Butyric Acid and Indole-3-Acetic Acid in Arabidopsis Hypocotyls Using Stable Isotope Labeling

Transport of Indole-3-Butyric Acid and Indole-3-Acetic Acid in Arabidopsis Hypocotyls Using Stable Isotope Labeling

Transport of the Two Natural Auxins, Indole-3-Butyric Acid and Indole-3-Acetic Acid, in Arabidopsis

Indole-3-butyric acid in plants: occurrence, synthesis, metabolism and transport

Contact Info

Product

Resources

About