Indole-3-acetic acid transport in apical dominance: a quantitative approach. Influence of endogenous and exogenous IAA apical source on inhibitory power of IAA transport

1996 ◽  
Vol 19 (1) ◽  
pp. 1-5 ◽  
Author(s):  
A. A. Kotov
1979 ◽  
Vol 63 (6) ◽  
pp. 1217-1219 ◽  
Author(s):  
Joseph Riov ◽  
Raphael Goren

2021 ◽  
Author(s):  
Arnaud-Thierry Djami-Tchatchou ◽  
Zipeng Alex Li ◽  
Paul Stodghill ◽  
Melanie J. Filiatrault ◽  
Barbara N. Kunkel

The auxin indole-3-acetic acid (IAA) is a plant hormone that not only regulates plant growth and development but also plays important roles in plant-microbe interactions. We previously reported that IAA alters expression of several virulence-related genes in the plant pathogen Pseudomonas syringae pv. tomato strain DC3000 ( Pto DC3000). To learn more about the impact of IAA on regulation of Pto DC3000 gene expression we performed a global transcriptomic analysis of bacteria grown in culture, in the presence or absence of exogenous IAA. We observed that IAA repressed expression of genes involved in the Type III secretion (T3S) system and motility and promoted expression of several known and putative transcriptional regulators. Several of these regulators are orthologs of factors known to regulate stress responses and accordingly expression of several stress response-related genes was also upregulated by IAA. Similar trends in expression for several genes were also observed by RT-qPCR. Using an Arabidopsis thaliana auxin receptor mutant that accumulates elevated auxin, we found that many of the P. syringae genes regulated by IAA in vitro were also regulated by auxin in planta . Collectively the data indicate that IAA modulates many aspects of Pto DC3000 biology, presumably to promote both virulence and survival under stressful conditions, including those encountered in or on plant leaves. IMPORTANCE Indole-3-acetic acid (IAA), a form of the plant hormone auxin, is used by many plant-associated bacteria as a cue to sense the plant environment. Previously, we showed that IAA can promote disease in interactions between the plant pathogen Pseudomonas syringae strain Pto DC000 and one of its hosts, Arabidopsis thaliana . However, the mechanisms by which IAA impacts the biology of Pto DC3000 and promotes disease are not well understood. Here we demonstrate that IAA is a signal molecule that regulates gene expression in Pto DC3000. The presence of exogenous IAA affects expression of over 700 genes in the bacteria, including genes involved in Type III secretion and genes involved in stress response. This work offers insight into the roles of auxin promoting pathogenesis.


2019 ◽  
Vol 136 ◽  
pp. 07002
Author(s):  
Le Liang ◽  
Wanjia Tang ◽  
Xuemei Peng ◽  
Jing Lu ◽  
Han Liu ◽  
...  

Indole-3-acetic acid (IAA) plays crucial roles in plant growth and stress tolerance. In present study, the effects of spraying different concentrations (0, 25, 50, 100 and 200 μmol/L) of IAA on the growth and cadmium (Cd) accumulation in lettuce (Lactuca sativa) were investigated. The lettuce exposed to Cd exhibited a substantial decline in growth, and the Cd content of them significantly increased. Spraying exogenous IAA resulted in alleviating the inhibitory of Cd toxicity to lettuce. The dry weight in shoots of lettuce increased by spraying with IAA compared with the Cd treatment alone, but the dry weight of roots had no significantly differences. Although exogenous IAA increased the root Cd content, it significantly reduced shoot Cd content, indicating its role in Cd transport. Therefore, spraying IAA effectively alleviated Cd toxicity and reduced Cd uptake in the edible parts of lettuce, and the 100 μmol/L IAA was the optimal dose.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 541h-542
Author(s):  
Shiow Y. Wang ◽  
Miklos Faust ◽  
Michael J. Line

The effect of Indole-3-acetic acid (IAA) on apical dominance in apple (Malus domestica Borkh.) buds was examined by studying changes In proton density (free water) and membrane lipid composition in lateral buds. Decapitation induced budbreak and enhanced lateral bud growth. IAA replaced apical control of lateral bud paradormancy. Maximal inhibition was obtained when IAA was applied immediately after the apical bud was removed. Delaying this application weakens the effect of IAA. An increase in proton density in lateral buds was observable 2 days after decapitation, whereas the change in membrane lipid composition occurred 4 days later. Decapitating the terminal bud induced an increase in membrane galacto- and phospholipids. and the ratio of unsaturated to corresponding saturated fatty acids. Decapitation also induced a decrease in the ratio of free sterols to phospholipids in lateral buds. Application of IAA to the terminal end of decapitated shoots inhibited the increase of proton density and prevented changes in the membrane lipid composition of lateral buds.


1993 ◽  
Vol 71 (12) ◽  
pp. 1645-1650 ◽  
Author(s):  
Jin-Hao Liu ◽  
Ilabanta Mukherjee ◽  
David M. Reid

Adventitious root formation by the hypocotyl cuttings of sunflower seedlings was greatly affected by the pH of buffered and unbuffered solutions bathing their basal portion. Exposure to low pH for 5 h after original root excision promoted root formation. Reduction of endogenous indole-3-acetic acid movement from the cotyledons and shoot apex was achieved by using N-1-naphthylphthalamic acid (an inhibitor of indole-3-acetic acid transport) and by removal of the cotyledons and shoot apex. Both the inhibitor and organ removal inhibited adventitious root formation, but acidic conditions could, to varying degrees, overcome this inhibition. Acidic conditions also increased the rate of [3H]indole-3-acetic acid uptake from the solutions around the hypocotyl bases and the rate of [3H]indole-3-acetic acid movement from cotyledons to the hypocotyl bases. Thus, acidic conditions may stimulate rooting by increasing the rate of basipetal indole-3-acetic acid transport to the zone of root initiation. These experiments show that in studies of the effects of various substances on rooting, the experimenter must be aware of these pH effects and take appropriate precautions. Key words: adventitious roots, auxin, indole-3-acetic acid, Helianthus annuus, pH.


Planta ◽  
2004 ◽  
Vol 221 (1) ◽  
pp. 39-47 ◽  
Author(s):  
Rafaël Smets ◽  
Jie Le ◽  
Els Prinsen ◽  
Jean-Pierre Verbelen ◽  
Henri A. Van Onckelen

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