Response of Root Growth and Development to Nitrogen and Potassium Deficiency as well as microRNA-Mediated Mechanism in Peanut (Arachis hypogaea L.).

Lijie Li,Kyle E Davis,Fei Li,Qian Li,Xiaoping Pan,Zhiyong Zhang,Thomas Elliott Thornburg,Sando Oo,Guo Wang,Yanzhong Zhou,Jia Liu,Caitlin Patterson,Isaac Seth Pratt,Julia Elise Fontana,Wanying Liu,Baohong Zhang

doi:10.3389/fpls.2021.695234

Abstract

The mechanism of miRNA-mediated root growth and development in response to nutrient deficiency in peanut (Arachis hypogaea L.) is still unclear. In the present study, we found that both nitrogen (N) and potassium (K) deficiency resulted in a significant reduction in plant growth, as indicated by the significantly decreased dry weight of both shoot and root tissues under N or K deficiency. Both N and K deficiency significantly reduced the root length, root surface area, root volume, root vitality, and weakened root respiration, as indicated by the reduced O2 consuming rate. N deficiency significantly decreased primary root length and lateral root number, which might be associated with the upregulation of miR160, miR167, miR393, and miR396, and the downregulation of AFB3 and GRF. The primary and lateral root responses to K deficiency were opposite to that of the N deficiency condition. The upregulated miR156, miR390, NAC4, ARF2, and AFB3, and the downregulated miR160, miR164, miR393, and SPL10 may have contributed to the growth of primary roots and lateral roots under K deficiency. Overall, roots responded differently to the N or K deficiency stresses in peanuts, potentially due to the miRNA-mediated pathway and mechanism.

Highlights

Cultivated peanut (Arachis hypogaea L.) is one of the three major legume grain and oilseed crops in China, with a planting area of over 5.0 × ha and annual pod yields of more than 1.6 × t in recent years, which plays a significant role in ensuring nutritional food security in China (Zhang et al, 2020)
Compared with the seedlings cultured in the normal nutrient solutions, the dry weight of shoot, root, and total plant of the seedlings cultured in N deficiency nutrient solutions on the 8th day decreased by 29.67, 25.73, and 18.60%, respectively, and that of the seedlings cultured in K deficiency nutrient solutions on 8th day decreased by 32.97, 27.15, and 14.29%, respectively
Compared with the seedlings cultured in the normal nutrient solutions, the primary root length and the lateral root number of the seedlings cultured in N deficiency nutrient solutions on the 8th day decreased by 44.89 and 22.49%, respectively, and that of the seedlings cultured in K deficiency nutrient solutions on 8th day increased by 59.04 and 71.46%, respectively

Summary

Introduction

Cultivated peanut (Arachis hypogaea L.) is one of the three major legume grain and oilseed crops in China, with a planting area of over 5.0 × ha and annual pod yields of more than 1.6 × t in recent years, which plays a significant role in ensuring nutritional food security in China (Zhang et al, 2020). Since the soil has been frequently overexploited in modern agricultural practices, nitrogen (N) and potassium (K) have been the microRNAs and Nutrient Deficiency in Peanut important limiting factors. They were often frequently supplemented in the form of fertilizers (Kuicheski et al, 2015). In China, more than one-third of cultivated soil is in the state of K deficiency (soil available K content is 50–70 mg/kg) or serious K deficiency (soil available K content is less than 50 mg/kg; Wang and Wu, 2009) It is of great significance for optimizing nutrient management, the supply of N and K in balance with crop demand and for the genetic improvement of peanut to explore the response mechanism of N deficiency and K deficiency in peanut

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Discussion

Conclusion