Biology subjects

Yoda, A.

Publications and source records attributed to Yoda, A..

3 recordsLinked to original sources

bioRxiv2022

Identification of a Prunus MAX1 Homolog as a Unique Strigol Synthase from Carlactone Bypassing 5-Deoxystrigol

Strigol was the first strigolactone (SL) to be discovered, but the biosynthetic pathway remains elusive. Here, through rapid gene screening using a microbial SL-producing platform, we functionally identified a strigol synthase (PpMAX1c, a cytochrome P450 711A enzyme) in Prunus that synthesizes strigol directly from the SL precursor carlactone through catalyzing multi-step oxidations and C-ring cyclization, bypassing the synthesis of 5-deoxystrigol. The function of PpMAX1c was validated through reconstructing the biosynthesis of strigol in Nicotiana benthamiana. Additional genomic analysis and functional verification confirm that peach also encodes an orobanchol synthase (PpCYP722C, a cytochrome P450 722C enzyme), which hints at the presence of both strigol-type and orobanchol-type SLs in peach and was confirmed through metabolic analysis of peach seedlings. This work highlights the catalytic diversity of the largely unexplored family of CYP711A homologs and sets the foundation to characterize the roles of different types of SLs in the economically important Prunus.

biochemistry↗

bioRxiv2022

Canonical Strigolactones Are Not the Tillering-Inhibitory Hormone but Rhizospheric Signals in Rice

The plant hormones strigolactones (SLs) regulate shoot branching and mediate the communication with symbiotic mycorrhizal fungi, but also with noxious root parasitic weeds, such as Striga spp. SLs derive from carlactone (CL) and are divided structurally into canonical and non-canonical SLs. However, the questions about particular biological functions of the two groups and the identification of the SL that inhibits shoot branching are still unanswered, hampering targeted modification of SL pattern towards improving plant architecture and resistance against Striga. Here, we reported that 4-deoxyorobanchol (4DO) and orobanchol, the two canonical SLs in rice, do not have major role in determining rice shoot architecture. CRISPR/Cas9 mediated Osmax1-900 mutants, lacking these two SLs, do not show the high tillering and dwarf phenotype typical for SL-deficient plants. However, the absence of 4DO and orobanchol in root exudates significantly decreased their capability in inducing Striga seed germination, while caused only a delay in root colonization by mycorrhizal fungi. To confirm the genetic evidence, we used the SL-biosynthesis inhibitor TIS108. Our results showed that TIS108 is a MAX1-specific inhibitor that lowers 4DO and orobanchol synthesis, conferring a resistance to Striga without a severe impact on rice architecture. Hence, our work uncovers the specific function of canonical SLs as rhizospheric signals and paves the way for establishing chemical and genetic based approaches for combating the root parasitic weeds, by targeted depletion of their release.

plant biology↗

bioRxiv2021

An ancestral function of strigolactones as symbiotic rhizosphere signals

In flowering plants, carotenoid-derived strigolactones (SLs) have dual functions as hormones that regulate growth and development, and as rhizosphere signaling molecules that induce symbiosis with arbuscular mycorrhizal (AM) fungi. Here, we report the identification of bryosymbiol (BSB), a previously unidentified SL from the bryophyte Marchantia paleacea. BSB is also found in vascular plants, indicating that it is ancestral in land plants. BSB synthesis is enhanced at AM symbiosis permissive conditions and BSB deficient mutants are impaired in AM symbiosis. In contrast, the absence of BSB synthesis has little effect on the growth and gene expression. We show that the introduction of the SL receptor of Arabidopsis renders M. paleacea cells BSB-responsive. These results suggest that BSB is not perceived by M. paleacea cells due to the lack of cognate SL receptors. We propose that SLs originated as AM symbiosis-inducing rhizosphere signaling molecules and were later recruited as plant hormone.

plant biology↗