AUTHOR=Zobrist Jacob D. , Martin-Ortigosa Susana , Lee Keunsub , Azanu Mercy K. , Ji Q , Wang Kan 

TITLE=Transformation of Teosinte (Zea mays ssp. parviglumis) via Biolistic Bombardment of Seedling-Derived Callus Tissues

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.773419

DOI=10.3389/fpls.2021.773419

ISSN=1664-462X

ABSTRACT=<p>Modern maize exhibits a significantly different phenotype than its wild progenitor teosinte despite many genetic similarities. Of the many subspecies of <italic>Zea mays</italic> identified as teosinte, <italic>Zea mays</italic> ssp. <italic>parviglumis</italic> is the most closely related to domesticated maize. Understanding teosinte genes and their regulations can provide great insights into the maize domestication process and facilitate breeding for future crop improvement. However, a protocol of genetic transformation, which is essential for gene functional analyses, is not available in teosinte. In this study, we report the establishment of a robust callus induction and regeneration protocol using whorl segments of seedlings germinated from mature seeds of <italic>Zea parviglumis</italic>. We also report, for the first time, the production of fertile, transgenic teosinte plants using the particle bombardment. Using herbicide resistance genes such as mutant acetolactate synthase (<italic>Als</italic>) or bialaphos resistance (<italic>bar</italic>) as selectable markers, we achieved an average transformation frequency of 4.17% (percentage of independent transgenic events in total bombarded explants that produced callus). Expression of visual marker genes of red fluorescent protein <italic>tdTomato</italic> and β-glucuronidase (<italic>gus</italic>) could be detected in bombarded callus culture and in T1 and T2 progeny plants. The protocol established in this work provides a major enabling technology for research toward the understanding of this important plant in crop domestication.</p>