Gibberellin stimulates regrowth after defoliation of sheepgrass (Leymus chinensis) by regulating expression of fructan-related genes
Gibberellins (GAs) affect forage growth and development; however, it is largely unknown how GAs regulate the metabolism of fructan (an important polysaccharide reserve in many cereals) and the regrowth of forage plants after defoliation. To explore the mechanism of the responses of defoliated sheepgrass [Leymus chinensis (Trin.) Tzvel] to GA, we sprayed defoliated sheepgrass with GA3 and/or paclobutrazol (PAC; an inhibitor of GA biosynthesis) and analyzed the growth characteristics, carbohydrate contents, and transcript levels of genes related to GA metabolism, GA signal transduction, and fructan metabolism. The results showed that spraying exogenous GA3 onto defoliated sheepgrass promoted leaf and internode elongation, while spraying with PAC inhibited leaf and internode elongation, compared with the control. Spraying GA3 onto defoliated sheepgrass also altered the fructan content by extending the period of fructan utilization. At the transcriptional level, exogenous GA3 increased the transcript levels of genes related to GA metabolism in the sheath. Taken together, our results suggest that exogenous GA3 stimulates the regrowth of defoliated sheepgrass regrowth by regulating GA and fructan-related genes, and by promoting endogenous GA synthesis, fructan metabolism, and signaling.
KeywordsLeymus chinensis Defoliation Gibberellin Fructan Regrowth
This work was supported by the National Basic Research Program of China (“973”, 2014CB138704), the National Natural Science Foundation of China (31470411), and the National High Technology Research and Development Program of China (“863”, 2011AA100209).
- Berthier A, Desclos M, Amiard V, Morvan-Bertrand A, Demmig-Adams B, Adams WW, Turgeon R, Prud’homme MP, Noiraud-Romy N (2009) Activation of sucrose transport in defoliated Lolium perenne L.: an example of apoplastic phloem loading plasticity. Plant Cell Physiol 50:1329–1344CrossRefPubMedGoogle Scholar
- Lee JM, Donaghy DJ, Sathish P, Roche JR (2010) Perennial ryegrass regrowth after defoliation—physiological and molecular changes. Proc N Z Grassl Assoc 72:127–134Google Scholar
- Yamamoto S, Mino Y (1998) Effect of exogenous plant bioactive substances on phleinase induction in stem base of orchardgrass. Grassland Science 43:380–384Google Scholar