Medicago scutellata, a wild forage species well adapted to calcareous soils, behaves upon Fe deficiency as a Strategy I one, with a marked capacity for synthesizing flavins (riboflavin and three hydroxylated riboflavin derivatives), which becomes more intense at high pH. Results also show that this species is capable of exporting a large amount of flavins to the external medium, both at pH 5.5 and 7.5. This is the first report of a species having a major flavin secretion at pH 7.5, in contrast with the very low flavin secretion found at this pH in other flavin-producing species such as Beta vulgaris and M. truncatula. These results provide further support to the hypothesis that flavin secretion is relevant for Fe acquisition at high pH, and open the possibility to improve the Fe-efficiency responses in legumes of agronomic interest.
This paper, published in the journal Plant Science, continues the recent collaboration on Fe deficiency between the EEAD-CSIC and the Ferdowsi University of Mashhad, Iran (Gheshlaghi et al. 2019, J Plant Nutr Soil Sci 182 (4): 607-624 (2019) ►; Gheshlaghi et al. 2020, Plant Soil 446, 43-63 ►). The first author of these studies, Zahra Gheshlaghi, had a 6-month pre-doctoral FPI stage in the EEAD in 2017-2018.
Gheshlaghi Z, Luis-Villarroya A, Álvarez-Fernández A, Khorassani R, Abadía J (2020) Root accumulation and secretion of flavins by Medicago scutellata in response to iron deficiency. Plant Science Q1, in press (doi: 10.1016/j.plantsci.2020.110664) ►.