AUTHOR=Zafar Kashaf , Khan Muhammad Zuhaib , Amin Imran , Mukhtar Zahid , Yasmin Sumera , Arif Muhammad , Ejaz Khansa , Mansoor Shahid 

TITLE=Precise CRISPR-Cas9 Mediated Genome Editing in Super Basmati Rice for Resistance Against Bacterial Blight by Targeting the Major Susceptibility Gene

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 11 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2020.00575

DOI=10.3389/fpls.2020.00575

ISSN=1664-462X

ABSTRACT=Basmati rice is famous for its flavor, aroma and long grain around the globe. Its demand is increasing worldwide especially in Asia. However, its production is threatened by various problems faced in the field which results in major crop losses. One of the major problems is bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo). Xoo hijacks the host machinery by activating the susceptibility genes (OsSWEET family genes), using its endogenous transcription activator like effectors (TALEs). TALEs have effector binding elements (EBEs) in the promoter region of OsSWEET genes. Out of six well-known TALEs found to have EBEs in Clade III SWEET genes, four are present in OsSWEET14 gene’s promoter region. Thus, targeting the promoter of OsSWEET14 is very important for creating broad-spectrum resistance. To engineer resistance against bacterial blight, we established CRISPR-Cas9 mediated genome editing in Super Basmati rice by targeting 4 EBEs present in the promoter of OsSWEET14. We were able to get 4 different Super Basmati lines (SB-E1, SB-E2, SB-E3 and SB-E4) having edited EBEs of three TALEs (AvrXa7, PthXo3 and TalF). The edited lines were then evaluated in triplicate for resistance against bacterial blight by choosing one of the locally isolated virulent Xoo strain having AvrXa7 and infecting Super Basmati. The lines having deletions in EBE of AvrXa7 showed resistance against Xoo strain. Thus, it was confirmed that edited EBEs provide resistance against their respective TALEs present in Xoo strains. In this study up to 9% editing efficiency was obtained. Our findings showed that CRISPR-Cas9 can be harnessed to generate resistance against bacterial blight in indigenous varieties against locally prevalent Xoo strains.