Blue light suppression alters cytokinin homeostasis in wheat leaves senescing under shading stress

0495316 - ÚEB 2019 RIV FR eng J - Journal Article
Marchetti, C. - Škrabišová, M. - Galuszka, P. - Novák, Ondřej - Causin, V.
Blue light suppression alters cytokinin homeostasis in wheat leaves senescing under shading stress.
Plant Physiology and Biochemistry. Roč. 130, SEP (2018), s. 647-657. ISSN 0981-9428
R&D Projects: GA MŠMT(CZ) LO1204
Institutional support: RVO:61389030
Keywords : zeatin-type cytokinins * leaf senescence * cis-zeatin * oxidase/dehydrogenase genes * subcellular-localization * arabidopsis * maize * metabolism * expression * rice * Blue light * Cytokinin metabolism * Gene expression * Leaf senescence * Shading stress * Triticum aestivum
OECD category: Plant sciences, botany
Impact factor: 3.404, year: 2018

Blue light (BL) suppression accelerates the senescence rate of wheat (Triticum aestivum L.) leaves exposed to shading. In order to study whether this effect involves the alteration of different cytokinin (CK) metabolites, CK-degradation, as well as the expression profile of genes responsible of CK-perception,inactivation,reactivation and/orturnover, leaf segments of 30 day-old plants were placed in boxes containing bi-distilled water and covered with blue (B) or green (G) light filters, which supplied a similar irradiance but differed in the percentage of BL transmitted (G < < B). A neutral (N) filter was used as control. When appropriate, different CK metabolites or an inhibitor of CK-degradation were added in order to alter the endogenous CK levels. A rapid decrement of trans-zeatin (tZ) and cis-zeatin (cZ) content was observed after leaf excision, which progressed at a higher rate in treatment G than in the control and B treatments. Senescence progression correlated with an accumulation of glycosylated forms (particularly cZ-derivatives), and an increment of CK-degradation, both of which were slowed in the presence of BL. On the contrary, CK-reactivation (analyzed through TaGLU1-3 expression) was delayed in the absence of BL. When different CK were exogenously supplied, tZ was the only natural free base capable to emulate the senescence-retarding effect of BL. Even though the signaling components involved in the regulation of senescence rate and CK-homeostasis by BL remain elusive, our data suggest that changes in the expression profile and/or functioning of the transcription factor HY5 might play an important role.
Permanent Link: http://hdl.handle.net/11104/0288310