Fig. 6

SPL13 interacts with proteins involved in photosynthesis process, stress alleviation, and specialized metabolite biosynthesis. a Coomasie stained SDS-PAGE gel, b a proposed tissue-specific drought tolerance model modulated by miR156/SPL13. The diagrammatic representation shows a tissue-specific miR156/SPL13 regulation module in response to drought tolerance. miR156 is induced by drought stress, which in turn silences SPL13 [2]. Reduced expression of SPL13 driven by miR156 and enhanced level of WD40–1 enhances DFR [15], together with less inactivation of GSK3 signalling with PAL, CHSs, and DFR result in accumulation of anthocyanins mainly in stem tissues. In moderate miR156OE plants, primary metabolites such as GABA, proline and sugars also accumulate for carbon-to-nitrogen balance and osmotic homeostasis. Induction of miR156 during drought stress also enhances phenotypic plasticity, such as longer roots and higher biomass to access more water from the rhizosphere. With reduced SPL13 expression and miR156OE, higher photosynthesis efficiency is also achieved during drought stress. The most prominent differential protein bands present in immuno-precipitated 35S::SPL13-GFP alfalfa plants are indicated with black arrow in ‘a’. Abbreviations in ‘b’ represent: CHS, Chalcone synthase; DFR, dihydroflavonol-4-reductase; GDSL, Gly-Asp- Ser-Leu –lipase; GSK, Glycogen synthase kinase-3; IFR, Isoflavone reductase; PAL, Phenylalanine Ammonia-Lyase; PDH, Proline Dehydrogenase