Interactive impact of potassium and arbuscular mycorrhizal fungi on the root morphology and nutrient uptake of sweet potato (Ipomoea batatas L.)

Jie Yuan; Kun Shi; Xiaoyue Zhou; Lei Wang; Cong Xu; Hui Zhang; Guopeng Zhu; Chengcheng Si; Jidong Wang; Yongchun Zhang

doi:10.3389/fmicb.2022.1075957

Interactive impact of potassium and arbuscular mycorrhizal fungi on the root morphology and nutrient uptake of sweet potato (Ipomoea batatas L.)

Front Microbiol. 2023 Jan 9:13:1075957. doi: 10.3389/fmicb.2022.1075957. eCollection 2022.

Authors

Jie Yuan^{1

2}, Kun Shi^{1

2

3}, Xiaoyue Zhou^{1

2

3}, Lei Wang^{1

2}, Cong Xu^{1

2}, Hui Zhang^{1

2}, Guopeng Zhu³, Chengcheng Si³, Jidong Wang^{1

2}, Yongchun Zhang^{1

2}

Affiliations

¹ Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China.
² National Agricultural Experimental Station for Agricultural Envrionment, Nanjing, Jiangsu, China.
³ College of Horticulture, Hainan University, Haikou, Hainan, China.

Abstract

Sweet potato is a typical "potassium (K)-favoring" food crop and strongly dependent on arbuscular mycorrhizal fungi (AMF). Recent studies show the importance of K and AMF to morphology optimization and nutrient uptake regulation of sweet potato; meanwhile, the interaction exists between K and K use efficiency (KIUE) in sweet potato. To date, only a few studies have shown that AMF can improve plant K nutrition, and whether the benefits conferred by AMF on plant are related to K remains unclear. In this study, low-KIUE genotype "N1" and high-KIUE genotype "Xu28" were used as experimental sweet potato; Funneliformis mosseae (FM) and Claroideoglomus etunicatum (CE) were used as experimental AMF. In a pot experiment, plants "N1" and "Xu28" were inoculated with FM or CE, and applied with or without K fertilizer to uncover the effects of K application and AMF inoculation on the root morphology and nutrient absorption of sweet potato during their growing period. Results demonstrated that AMF inoculation-improved root morphology of sweet potato highly relied on K application. With K application, AMF inoculation significantly increased root tip number of "N1" in the swelling stage and optimized multiple root morphological indexes (total root length, root surface area, root volume, root diameter, root branch number, and root tip number) of "Xu28" and CE had the best optimization effect on the root morphology of "Xu28". In addition, CE inoculation significantly promoted root dry matter accumulation of "Xu28" in the swelling and harvesting stages, coordinated aerial part and root growth of "Xu28", reduced the dry matter to leaf and petiole, and was beneficial to dry matter allocation to the root under conditions of K supply. Another promising finding was that CE inoculation could limit K allocation to the aboveground and promote root K accumulation of "Xu28" under the condition with K application. The above results lead to the conclusion that K and CE displayed a synergistic effect on root development and K acquisition of high-KIUE "Xu28". This study could provide a theoretical basis for more scientific application of AMF in sweet potato cultivation and will help further clarify the outcomes of plant-K-AMF interactions.

Keywords: arbuscular mycorrhizal fungi; nutrient uptake; potassium; root morphology; sweet potato; tuberous root yield.

Grants and funding

This study was financially supported by the earmarked fund for CARS-10-Sweetpotato, the Jiangsu Agriculture Science and Technology Innovation Fund [CX (21)1009], the Key Research and Development Project of Jiangsu Province (BE2019378 and BE2021378), and Youth Joint Innovation Project 2022, Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences [ZCX (2022) 21].