赤黴素(GA)是調控植物生長發育的重要激素。DELLA蛋白會抑制GA的應答,而破壞DELLA蛋白則能夠增加GA信號的生成。最近,研究人員利用CRISPR/Cas9技術編輯了番茄中的PROCERA缺失突變體,從而產生了新型的半顯性矮化等位基因。
PROCERA是番茄中的DELLA蛋白。proTALEN是利用TALEN技術創製的PROCERA基因隱性突變體,該突變體株高增加,對GA和GA生物合成抑制劑多效唑不敏感。研究人員利用CRISPR/Cas9技術對proTALEN等位基因進行了進一步的編輯,產生了一批獲得性突變體。這些突變體影響了DELLA結構域的功能,其中一個等位基因pro GF8有12個胺基酸的插入和2個胺基酸的替換,可以進一步影響DELLA結構域中的LExLE模體。這個等位基因具有半顯性特徵,植株表現極端矮化,對外源GA3不敏感。只有當GA生物合成抑制劑多效唑存在時才會表現出對GA3微弱的應答。此外,pro GF8種子的發芽也存在異常。
Plant Biotechnology Journal, 18 October 2018
Characterization of a semidominant dwarfing PROCERA allele identified in a screen for CRISPR/Cas9-induced suppressors of loss-of-function alleles
Author
Zhiguo Zhu, Xiaojun Kang, Vai S. Lor, David Weiss, Neil Olszewski*
Department of Plant and Microbial Biology and the Microbialand Plant Genomics Institute, University of Minnesota, Minnesota
Abstract
Gibberellin (GA) is a plant hormone that regulates important growth processes including germination, flowering, and fruit development. DELLA proteins inhibit GA responses. GA signaling increases through GA triggered destruction of the DELLA protein. Several mutants with reduced stature due to mutations that stabilize the DELLA protein are known. Many of these mutations cause deletions within the DELLA domain. Here we report several new dwarfing alleles of the tomato DELLA protein, PROCERA, generated using the CRISPR/Cas9 system to create intragenic suppressors of two pro loss‐of‐function alleles. The new mutations affected the DELLA domain and one of the alleles, pro GF8, which has a 12 amino acid insertion and 2 amino acid substitution affecting the LExLE motif of DELLA domain was further characterized. This allele is semidominant. PRO/pro GF8 plants are extreme dwarfs and do not respond to exogenous GA3. However, a minor response to exogenous GA3 was found when it was applied together with the GA biosynthesis inhibitor paclobutrazol. Germination of PRO/pro GF8 seeds was delayed and pro GF8/proGF8 seeds did not germinate without scarification.
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