Molecular evidence for phytosiderophore‐induced improvement of iron nutrition of peanut intercropped with maize in calcareous soil

Abstract

Peanut/maize intercropping is a sustainable and effective agroecosystem that evidently enhances the Fe nutrition of peanuts in calcareous soils. So far, the mechanism involved in this process has not been elucidated. In this study, we unravel the effects of phytosiderophores in improving Fe nutrition of intercropped peanuts in peanut/maize intercropping. The maize ys3 mutant, which cannot release phytosiderophores, did not improve Fe nutrition of peanut, whereas the maize ys1 mutant, which can release phytosiderophores, prevented Fe deficiency, indicating an important role of phytosiderophores in improving the Fe nutrition of intercropped peanut. Hydroponic experiments were performed to simplify the intercropping system, which revealed that phytosiderophores released by Fe-deficient wheat promoted Fe acquisition in nearby peanuts and thus improved their Fe nutrition. Moreover, the phytosiderophore deoxymugineic acid (DMA) was detected in the roots of intercropped peanuts. The yellow stripe1-like (YSL) family of genes, which are homologous to maize yellow stripe 1 (ZmYS1), were identified in peanut roots. Further characterization indicated that among five AhYSL genes, AhYSL1, which was localized in the epidermis of peanut roots, transported Fe(III)-DMA. These results imply that in alkaline soil, Fe(III)-DMA dissolved by maize might be absorbed directly by neighbouring peanuts in the peanut/maize intercropping system.

Improved iron acquisition ofAstragalus sinicusunder low iron-availability conditions by soil-borne bacteriaBurkholderia cepacia

“…Fe often forms scarce solubility of Fe 3+ oxyhydroxides that are not easily assimilated by most plant species (Lemanceau et al 2009). Many crop plants such as barely and peanut often exhibit Fe deficiency-induced leaf chlorosis under alkaline conditions (Takahashi et al 2001;Xiong et al 2013). Calcareous soils account for about a third of the earth's crust, Fe deficiency thus becomes one of major abiotic stresses that seriously affect plant growth and development, crop yield and quality (Takahashi et al 2001;Xiong et al 2013;Zhou et al 2016).…”

“…Many crop plants such as barely and peanut often exhibit Fe deficiency-induced leaf chlorosis under alkaline conditions (Takahashi et al 2001;Xiong et al 2013). Calcareous soils account for about a third of the earth's crust, Fe deficiency thus becomes one of major abiotic stresses that seriously affect plant growth and development, crop yield and quality (Takahashi et al 2001;Xiong et al 2013;Zhou et al 2016). Fe deficiency is also one of the most wide-ranging nutrient deficiency in human dietary, which causes adverse impacts on approximate 2 billion people health, and even 0.8 million death annually (Murgia et al 2012).…”

Review on iron availability in soil: interaction of Fe minerals, plants, and microbes

“…It is interesting to note that rice, a strategy II plant releasing PS s (2′-deoxymugineic acid [DMA]) and taking up the entire Fe III -PS complexes, is also able to take up directly Fe II from the soil solution, definitely an advantage when rice is cultivated in submerged conditions (Ishimaru et al 2006). On the contrary, it has been recently demonstrated that a Fe III complex with DMA, a PS s released by maize roots, could be absorbed directly by roots of a neighboring dicot using a transporter codified by a gene belonging to the yellow stripe1-like (YSL) family and located at the root epidermis (Xiong et al 2013), representing a valid opportunity in Fe acquisition process of dicots when intercropped with monocots. With respect to the possibility that plants could utilize Fe III -MS s complexes as Fe source, due to their very high stability constant, the Fe exchange between Fe III -MS s and PS s could be very limited.…”

Characterizing the expression of genes involved in iron transport inPakistani peanut varieties under iron deficiency stress

“…The Fe concentration of young leaves of BARI-2000 and Chakori was nonsignificantly different. The expression of AhYSL3.1 was higher in roots and young and old leaves under Fe-sufficient conditions (Xiong et al, 2013).…”

“…For each replication in the hydroponics experiment, young and old leaves and roots of each plant of a variety were sampled separately and ground in an appropriate buffer, and RNA was extracted using the RNeasy Kit (QIAGEN). The genes (AhIRT1, AhFRO1, AhNRAMP1, AhYSL1, AhYSL3.1, AhYSL4, and AhYSL6) were selected based on their positions in corresponding pathways in groundnut/ maize intercropping and Arabidopsis (Petit et al, 2001;Ding et al, 2009Ding et al, , 2010Xiong et al, 2012Xiong et al, , 2013Xiong et al, , 2014. YSL genes are important in cross-membrane and long-distance transport of Fe.…”