Competitive interactions in two different plant species: Do grassland mycorrhizal communities and nitrogen addition play the same game?

Ali Bahadur; Shengjing Jiang; Wei Zhang; Wasim Sajjad; Muhammad Usman; Fahad Nasir; Muhammad Amir Zia; Qi Zhang; Jianbin Pan; Yongjun Liu; Tuo Chen; Huyuan Feng

doi:10.3389/fpls.2023.1084218

Competitive interactions in two different plant species: Do grassland mycorrhizal communities and nitrogen addition play the same game?

Front Plant Sci. 2023 Mar 13:14:1084218. doi: 10.3389/fpls.2023.1084218. eCollection 2023.

Authors

Ali Bahadur^{1

2

3}, Shengjing Jiang⁴, Wei Zhang³, Wasim Sajjad³, Muhammad Usman⁵, Fahad Nasir⁶, Muhammad Amir Zia⁷, Qi Zhang², Jianbin Pan², Yongjun Liu², Tuo Chen³, Huyuan Feng²

Affiliations

¹ Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China.
² MOE Key Laboratory of Cell Activities and Stress Adaptation, School of Life Sciences, Lanzhou University, Lanzhou, China.
³ State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China.
⁴ State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China.
⁵ State Key Laboratory of Grassland Agroecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, Gansu, China.
⁶ Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, Jilin, China.
⁷ National Institute for Genomics and Advanced Biotechnology, National Agriculture Research Center, Islamabad, Pakistan.

Abstract

In the Tibetan Plateau grassland ecosystems, nitrogen (N) availability is rising dramatically; however, the influence of higher N on the arbuscular mycorrhizal fungi (AMF) might impact on plant competitive interactions. Therefore, understanding the part played by AMF in the competition between Vicia faba and Brassica napus and its dependence on the N-addition status is necessary. To address this, a glasshouse experiment was conducted to examine whether the grassland AMF community's inocula (AMF and NAMF) and N-addition levels (N-0 and N-15) alter plant competition between V. faba and B. napus. Two harvests took day 45 (1^st harvest) and day 90 (2^nd harvest), respectively. The findings showed that compared to B. napus, AMF inoculation significantly improved the competitive potential of the V. faba. In the occurrence of AMF, V. faba was the strongest competitor being facilitated by B. napus in both harvests. While under N-15, AMF significantly enhanced tissue N:P ratio in B. napus mixed-culture at 1^st harvest, the opposite trend was observed in 2^nd harvest. The mycorrhizal growth dependency slightly negatively affected mixed-culture compared to monoculture under both N-addition treatments. The aggressivity index of AMF plants was higher than NAMF plants with both N-addition and harvests. Our observation highlights that mycorrhizal associations might facilitate host plant species in mixed-culture with non-host plant species. Additionally, interacting with N-addition, AMF could impact the competitive ability of the host plant not only directly but also indirectly, thereby changing the growth and nutrient uptake of competing plant species.

Keywords: grassland AMF inoculum; host plant; nitrogen deposition; non-host plant; plant competition.

Grants and funding

This work was supported by grants from the Second Tibetan Plateau Scientific Expedition and Research Program (2019QZKK0301), National Natural Science Foundation of China (NSFC) (31971445, and U21A20186), the Scientific Project of Gansu Province (18JR2TA019, 20JR5RA548), and the CAS-President’s International Fellowship Initiative (PIFI) Postdoctoral Fellowship (2021PB0072).