Microtubule-associated proteins regulate tomato fruit shape

Bao et al. reveal how microtubule-associated proteins regulate tomato fruit shape formation from a cell biology perspective.

 Plant Cell https://doi.org/10.1093/plcell/koad231

 Zhiru Bao and Pengwei Wang

National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, Hubei Province, China; 2. Hubei Hongshan Laboratory, Wuhan 430070, China

Background: Genes encoding microtubule-binding proteins have emerged as conserved trait loci for fruit shape regulation with important roles during domestication. While microtubule-binding proteins have been reported in many fruit crops, most studies were performed using forward genetics or population genetics approaches. Thus, in-depth molecular and cell biology insight is lacking.

Question: How are cortical microtubules organized in fruit tissue? From a cell biology perspective, which proteins regulate microtubule dynamics and organization in tomato fruits?

Findings: We identified the microtubule-associated proteins SlMAP70s and SlIQD21a as important regulators of tomato fruit shape. These proteins interact and affect microtubule stability, which may contribute to the re-arrangement of cortical microtubules and cell growth patterns underlying organ shape. Transgenic tomato lines over-expressing SlMAP70-1 produced elongated fruits with reduced cell circularity and microtubule anisotropy, while loss-of-function mutants exhibited flatter fruits. Fruits were further elongated in plants co-expressing both SlMAP70-1 and SlIQD21a.

Next steps: These findings shed light on the functional regulation of microtubule organization and provide a powerful approach for future studies on fruit shape regulation in fruit crops.


Zhiru Bao, Ye Guo, Yaling Deng, Jingze Zang, Junhong Zhang, Yingtian Deng, Bo Ouyang, Xiaolu Qu, Katharina Bürstenbinder and Pengwei Wang. (2023) Microtubule-associated protein SlMAP70 interacts with IQ67-domain protein SlIQD21a to regulate fruit shape in tomato. https://doi.org/10.1093/plcell/koad231