Dynamics in the rhizosphere and iron-uptake gene expression in peanut induced by intercropping with maize: role in improving iron nutrition in peanut.
The intercropping of maize with peanuts is an effective cropping practice. Indeed, peanut/maize intercropping reportedly improves the iron nutrition of peanuts in calcareous soils. The limited evidence available suggests that the improved Fe nutrition in intercropping is largely attributable to a rhizosphere effect of maize. In this study, the effects of peanut/maize intercropping on the Fe nutritional status of peanut associated with the dynamics of the rhizosphere processes and Fe uptake gene expression induced by the interaction of the two species at various growth days were investigated. The results suggest that an interspecific rhizosphere effect improves Fe nutrition in peanut, as shown by changes in the rhizosphere available Fe concentration, pH, and Olsen-P concentration, based on time-course changes in peanut-maize interaction. The increase in available Fe in the rhizosphere of peanut ranged from 0.2 to 2.64 mg kg(-1). The transition from the vegetative to reproductive stage was a key turning point in the time-course of changes in the rhizosphere processes in intercropping. There was more consistently positive effect of intercropping on peanut Fe nutrition after 53 days. Moreover, the expression of AhFRO1 and AhYSL1 was expressed at significantly higher level in intercropped peanuts compared to monocropped peanut at the vegetative stage, indicating a role for these genes in Fe improvement in intercropped peanuts. We conclude that the enhanced time-course changes in the rhizosphere processes and iron uptake gene expression with a consistent positive interspecific effect appear to be one of the mechanisms underlying the improved Fe nutrition in intercropped peanut plants.
Key Laboratory of Plant-Soil Interactions, MOE, Centre for Resource, Environment and Food Security, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
Xiaotong
X
Guo
Key Laboratory of Plant-Soil Interactions, MOE, Centre for Resource, Environment and Food Security, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
Hongchun
H
Xiong
Key Laboratory of Plant-Soil Interactions, MOE, Centre for Resource, Environment and Food Security, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
Hongyun
H
Shen
Key Laboratory of Plant-Soil Interactions, MOE, Centre for Resource, Environment and Food Security, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
Wei
W
Qiu
Key Laboratory of Plant-Soil Interactions, MOE, Centre for Resource, Environment and Food Security, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
Chunqiao
C
Ji
Key Laboratory of Plant-Soil Interactions, MOE, Centre for Resource, Environment and Food Security, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
Zhenjiao
Z
Zhang
Key Laboratory of Plant-Soil Interactions, MOE, Centre for Resource, Environment and Food Security, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China. Electronic address: zuoym@cau.edu.cn.
Yuanmei
Y
Zuo
D000383:Agriculture / Q000379:methods; D010367:Arachis / Q000502:physiology*; D018556:Crops, Agricultural; D038181:FMN Reductase / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D007501:Iron / Q000032:analysis* / Q000737:chemistry*; D018517:Plant Roots; D058441:Rhizosphere; D012987:Soil; D013997:Time Factors; D003313:Zea mays / Q000502:physiology*
D012987:Soil; D007501:Iron; D038181:FMN Reductase; C023903:ferric citrate iron reductase
AhFRO1 and AhYSL1 gene expression; Iron nutrition; Peanut/maize intercropping; Rhizosphere interaction