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狗尾草是旱地作物常見的一種雜草，屬C4植物。由於其基因組小（510Mb），序列完整；植株矮小（10-15cm），生活周期短（約6周），兩性花，雜交方便，種子產量高；可利用農桿菌介導法轉化，轉化效率高等一系列優勢，現在已被作為一種典型的C4模式生物，被用作C4光合相關研究。
為了尋找花序發育相關基因，改良花序形態從而提高產量，研究人員利用亞硝基甲脲（NMU）誘變狗尾草（Setaria viridis），在2700個M2群體中找到了4個隱性的稀疏穗突變體spp1–spp4，他們的共同特徵是穗部分枝變少且不規則。利用群分法（bulked segregant analysis, BSA）及深度測序，定位到突變基因SvAUX1（AUXIN1）。AUX1編碼一種生長素轉運蛋白，其在花序發育和保持根的向地性方面具有重要的功能。玉米中的同源分析表明ZmAUX1在玉米中具有同樣的功能。
這一研究結果表明了狗尾草作為C4模式植物，在玉米等其他C4作物的基因挖掘和功能研究方面所具有的重要作用。
Nature Plants, 3: 17054, 18 April 2017
Sparse panicle1 is required for inflorescence development in Setaria viridis and maize
Author
Pu Huang, Hui Jiang, Chuanmei Zhu……Mathew S. Box, Elizabeth A. Kellogg & Thomas P. Brutnell*
*: Donald Danforth Plant Science Center, USA
Abstract
Setaria viridis is a rapid-life-cycle model panicoid grass. To identify genes that may contribute to inflorescence architecture and thus have the potential to influence grain yield in related crops such as maize, we conducted an N-nitroso-N-methylurea (NMU) mutagenesis of S. viridis and screened for visible inflorescence mutant phenotypes. Of the approximately 2,700 M2 families screened, we identified four recessive sparse panicle mutants (spp1–spp4) characterized by reduced and uneven branching of the inflorescence. To identify the gene underlying the sparse panicle1 (spp1) phenotype, we performed bulked segregant analysis and deep sequencing to fine map it to an approximately 1 Mb interval. Within this interval, we identified disruptive mutations in two genes. Complementation tests between spp1 and spp3 revealed they were allelic, and deep sequencing of spp3 identified an independent disruptive mutation in SvAUX1 (AUXIN1), one of the two genes in the ∼1 Mb interval and the only gene disruption shared between spp1 and spp3. SvAUX1 was found to affect both inflorescence development and root gravitropism in S. viridis. A search for orthologous mutant alleles in maize confirmed a very similar role of ZmAUX1 in maize, which highlights the utility of S. viridis in accelerating functional genomic studies in maize.
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