Physiological and transcriptional responses in the iron-sulphur cluster assembly pathway under abiotic stress in peach (Prunus persica L.) seedlings

As one of the most indispensable element in mineral nutrition of plants, iron (Fe) is closely related to fruits quality and yield. However, molecular mechanisms towards Fe metabolism in fruit trees is largely unclear. In higher plants, iron-sulphur (Fe-S) cluster assembly occurs in chloroplasts, mitochondria and cytosol involving dozens of genes. In this study, we identified 44 putative Fe-S cluster assembly genes in peach (Prunus persica cv. 'Xiahui6'), and analyzed Fe-S cluster assembly gene expression profiles in response to abiotic stresses. Peach seedlings were more sensitive to iron deficiency, drought and salinity stress, evidenced in reduced photosynthetic performance and altered activity of nitrite reductase, succinate dehydrogenase and aconitase. In addition, Fe-S cluster assembly genes are differentially regulated by abiotic stresses. Iron depletion and drought stress are likely to affect Fe-S cluster assembly genes in leaves. Excess iron toxicity mainly induces Fe-S cluster assembly gene expression in roots, whereas salinity stress massively inhibits Fe-S cluster assembly gene expression in roots. Interestingly, we found that un-functional scaffolds are more prone to disappear during the long-term evolution in perennial woody plants. Our findings directly provide molecular basis for Fe metabolism in peach, and favorably reveal potential candidate genes for further functional determination.