Effects of SAG12-ipt and HSP18.2-ipt Expression on Cytokinin Production, Root Growth, and Leaf Senescence in Creeping Bentgrass Exposed to Drought Stress

By Emily Merewitz, T. Gianfagna, Bingru Huang. 2010

83 citations recorded by the source corpus.

Drought stress is a widespread abiotic stress that causes a decline in plant growth. Drought injury symptoms have been associated with an inhibition in cytokinin (CK) synthesis. The objectives of this study were to investigate whether expression of a gene (ipt) encoding the enzyme adenine isopentenyl phosphotransferase for CK synthesis ligated to a senescence-activated promoter (SAG12) or a heat shock promoter (HSP18.2) would improve drought tolerance in creeping bentgrass (Agrostis stolonifera) and to examine shoot and root growth responses to drought stress associated with changes in endogenous production of CK, and the proportional change in CK and abscisicacid(ABA) duetoipttransformation.MostSAG12-iptandHSP18.2-ipttransgeniclines exhibitedsignificantly higher turf quality, photochemical efficiency, chlorophyll content, leaf relative water content, and root:shoot ratio under drought stress than the null transformant or the wild-type 'Penncross' plants. Transgenic lines that had better growth and turf performance generally had higher CK content and a higher CK-to-ABA ratio, although the direct correlation of CK and ABA content with individual physiological parameters in individual lines was not clear. Our results demonstrated that expressing ipt resulted in the improvement of turf performance under drought stress in creeping bentgrass in some of the transgenic plants with SAG12-ipt orHSP18.2-ipt, which could be associated with the suppression of leaf senescence and promoting root growth relative to shoot growth due to the maintenance of higher CK level and a higher ratio of CK to ABA. Drought is a detrimental abiotic stress for plant growth, including perennial turfgrass species. A typical drought stress symptom in turfgrass is a decline in turf quality (TQ) resulting from leaf senescence, slow shoot and root growth, and leaf desiccation (Fry and Huang, 2004). Plant adaptation to drought stress has been associated with the hormonal regulation of these

Subfields: Ecology, Evolution, Behavior and Systematics, Environmental Chemistry, Plant Science

View Paper: https://www.semanticscholar.org/paper/fd5361298e45cee31b50799838582cf772cfd7ee

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In Environmental Chemistry

1. M. Dacosta
2. Yiwei Jiang
3. Bingru Huang
4. L. Cui
5. Jun Li
6. Yetang Wang
7. Jinglin Wang
8. A. Wahid

In Plant Science

1. M. Dacosta
2. Yiwei Jiang
3. Bingru Huang
4. I. Vaseva
5. Urs Feller
6. A. Wahid

Citations in the corpus

• Extreme climatic events: impacts of drought and high temperature on physiological processes in agronomically important plants (2014, background): “The relevance of the recovery phase after an extended drought period was emphasized by several groups (Merewitz et al., 2010; Vassileva et al., 2011; Yao et al., 2012).”
• Research Advances in Mechanisms of Turfgrass Tolerance to Abiotic Stresses: From Physiology to Molecular Biology (2014, background): “A recent study in transgenic creeping bentgrass with a gene (ipt encoding isopentyl transferase) controlling cytokinin synthesis has shown that increased endogenous production of cytokinins (CK) is associated with greater root viability under drought stress (Merewitz et al., 2010a).”