ARGOS8 variants generated by CRISPR‐Cas9 improve maize grain yield under field drought stress conditions

By Jinrui Shi, Huirong Gao, Hongyu Wang, H. Lafitte, Rayeann L. Archibald, Meizhu Yang, Salim M. Hakimi, Hua Mo, J. Habben. Plant Biotechnology Journal, 2016

775 citations recorded by the source corpus.

Summary Maize ARGOS8 is a negative regulator of ethylene responses. A previous study has shown that transgenic plants constitutively overexpressing ARGOS8 have reduced ethylene sensitivity and improved grain yield under drought stress conditions. To explore the targeted use of ARGOS8 native expression variation in drought‐tolerant breeding, a diverse set of over 400 maize inbreds was examined for ARGOS8 mRNA expression, but the expression levels in all lines were less than that created in the original ARGOS8 transgenic events. We then employed a CRISPR‐Cas‐enabled advanced breeding technology to generate novel variants of ARGOS8. The native maize GOS2 promoter, which confers a moderate level of constitutive expression, was inserted into the 5′‐untranslated region of the native ARGOS8 gene or was used to replace the native promoter of ARGOS8. Precise genomic DNA modification at the ARGOS8 locus was verified by PCR and sequencing. The ARGOS8 variants had elevated levels of ARGOS8 transcripts relative to the native allele and these transcripts were detectable in all the tissues tested, which was the expected results using the GOS2 promoter. A field study showed that compared to the WT, the ARGOS8 variants increased grain yield by five bushels per acre under flowering stress conditions and had no yield loss under well‐watered conditions. These results demonstrate the utility of the CRISPR‐Cas9 system in generating novel allelic variation for breeding drought‐tolerant crops.

Subfields: Molecular Biology, Plant Science

View Paper: https://www.semanticscholar.org/paper/6059eadd12ab11b1403e1c3131d614554db934d4

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Jian‐Kang Zhu

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Citations in the corpus

Genome Editing—Principles and Applications for Functional Genomics Research and Crop Improvement (2017, background): “…resistance in rice, maize, and flax and increased drought resistance in maize, via introduction of precise point mutations, insertion of new genes or precise promoter replacement (Svitashev et al., 2015; Endo et al., 2016b; Li et al., 2016c; Sauer et al., 2016; Sun et al., 2016a; Shi et al., 2017).”
Translating High-Throughput Phenotyping into Genetic Gain (2018, background): “Detecting significant yield differences in genome-edited variants similarly requires a high signal-to-noise ratio [64].”
The Pivotal Role of Ethylene in Plant Growth (2018, background): “Most interestingly, CRISPR/Cas9-engineered variants of maize with increased ZmARGOS8 expression levels show a higher grain yield under drought stress conditions, and also a mild but significant increase in plant height under well-watered conditions, albeit without grain yield advantage [44].”
Heat and Drought Stresses in Crops and Approaches for Their Mitigation (2018, background): “NAC gene/rice TF Maize ubiquitin 1 promoter/overexpression Enhanced tolerance to drought and salt stresses Wheat Saad et al., 2013 HVA1/barely Group 3 LEA - HVA1 Maize ubi1 promoter/overexpression Improved drought tolerance and field evaluation for drought tolerance Wheat Sivamani et al., 2000; Bahi”