Enhancing auxin accumulation in maize root tips improves root growth and dwarfs plant height

• Published in: Plant biotechnology journal Vol. 16; no. 1; pp. 86 - 99
• Main Authors: Li, Zhaoxia, Zhang, Xinrui, Zhao, Yajie, Li, Yujie, Zhang, Guangfeng, Peng, Zhenghua, Zhang, Juren
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01-01-2018; John Wiley and Sons Inc
• Subjects: Carbohydrates; Corn; Crop yield; Crop yields; Cultivation; Drought; Elongation; Environmental stress; Food industry; Food plants; Forage crops; Gene Expression Regulation, Plant - physiology; Growth; ideal plant type; Indoleacetic Acids - metabolism; Lodging; maize; Phenotypes; Plant Breeding; Plant growth; Plant Proteins - metabolism; Plant resistance; Plant Roots - growth & development; Plant Roots - metabolism; Proteins; root architecture modification; Roots; Skewed distributions; Tips; transgenic breeding; Transport; Vermiculite; yield; Zea mays - growth & development; Zea mays - metabolism; transgenic breeding; ideal plant type; root architecture modification; maize; yield
• ISSN: 1467-7644; 1467-7652
• DOI: 10.1111/pbi.12751

Summary
Maize is a globally important food, feed crop and raw material for the food and energy industry. Plant architecture optimization plays important roles in maize yield improvement. PIN‐FORMED (PIN) proteins are important for regulating auxin spatiotemporal asymmetric distribution in multiple plant developmental processes. In this study, ZmPIN1a overexpression in maize increased the number of lateral roots and inhibited their elongation, forming a developed root system with longer seminal roots and denser lateral roots. ZmPIN1a overexpression reduced plant height, internode length and ear height. This modification of the maize phenotype increased the yield under high‐density cultivation conditions, and the developed root system improved plant resistance to drought, lodging and a low‐phosphate environment. IAA concentration, transport capacity determination and application of external IAA indicated that ZmPIN1a overexpression led to increased IAA transport from shoot to root. The increase in auxin in the root enabled the plant to allocate more carbohydrates to the roots, enhanced the growth of the root and improved plant resistance to environmental stress. These findings demonstrate that maize plant architecture can be improved by root breeding to create an ideal phenotype for further yield increases.