AUTHOR=Li Juan , Wang Xi , Wei Junfeng , Miao Xinxin , Shang Xiaoyang , Li Lin 

TITLE=Genetic mapping and functional analysis of a classical tassel branch number mutant Tp2 in maize

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1183697

DOI=10.3389/fpls.2023.1183697

ISSN=1664-462X

ABSTRACT=<p>Tassel branch number is a key trait that contributes greatly to grain yield in maize (<italic>Zea mays</italic>). We obtained a classical mutant from maize genetics cooperation stock center, <italic>Teopod2</italic> (<italic>Tp2</italic>), which exhibits severely decreased tassel branch. We conducted a comprehensive study, including phenotypic investigation, genetic mapping, transcriptome analysis, overexpression and CRISPR knock-out, and tsCUT&amp;Tag of <italic>Tp2</italic> gene for the molecular dissection of <italic>Tp2</italic> mutant. Phenotypic investigation showed that it is a pleiotropic dominant mutant, which is mapped to an interval of approximately 139-kb on Chromosome 10 harboring two genes <italic>Zm00001d025786</italic> and <italic>zma-miR156h</italic>. Transcriptome analysis showed that the relative expression level of <italic>zma-miR156h</italic> was significantly increased in mutants. Meanwhile, overexpression of <italic>zma-miR156h</italic> and knockout materials of <italic>ZmSBP13</italic> exhibited significantly decreased tassel branch number, a similar phenotype with <italic>Tp2</italic> mutant, suggesting that <italic>zma-miR156h</italic> is the causal gene of <italic>Tp2</italic> and targets <italic>ZmSBP13</italic> gene. Besides, the potential downstream genes of <italic>ZmSBP13</italic> were uncovered and showed that it may target multiple proteins to regulate inflorescence structure. Overall, we characterized and cloned <italic>Tp2</italic> mutant, and proposed a zma-miR156h-ZmSBP13 model functioning in regulating tassel branch development in maize, which is an essential measure to satisfy the increasing demands of cereals.</p>