| 研究実績の概要 |
Through the physiological screening of auxin signaling and auxin transport mutants (e.g. aux1-7, pin2, pin3, pin4, tir1, slr1, axr1 and afb)a cold stress hypersensitive auxin mutant slr1 was identified. After identification of cold hypersensitive auxin mutant,next generation sequencing (NGS) was performed with the hypersensitive mutant (slr1) under cold stress. Root samples incubated at 4°C root for 12 h from the hypersensitive slr1 mutant and Col-0 and respective controls at 23°C were used for NGS.
A total of 4 small RNA libraries were constructed and was analyzed on Illumina genome analyzer. After removing low quality reads and adaptor sequences a total of 11,599,097; 11,162,513; 10,753,621 and 10,974,188 reads were generated from Col0 23°C, Col0 4°C, slr1 23°C and slr1 4°C respectively. These unique sequences ranged from 18 to 30 nucleotides in length. The most abundant size of small RNAs in the library was 21 nucleotides followed by 24 nucleotides in all the libraries.
Bioinformatic analysis of libraries resulted in identification of 101 microRNA(s) involved in auxin signaling during cold stress. Around ten candidate known microRNAs, which responded deferentially between col-0 and slr1 under cold were selected for further studies. These microRNAs include ath-miR166, ath-miR 167, ath-miR 169, ath-miR 172, ath-miR 393, ath-miR 394, ath-miR 399, ath-miR 5021 and ath-miR 5653. The wet lab validation of these selected candidate microRNAs are under process.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
1: 当初の計画以上に進展している
理由
The work is progressing as per planning submitted initially. The hypothesis, "auxin is involved in cold stress response" is validated by identification of a cold hypersensitive auxin signaling mutant slr1. The NGS approach to identify the miRNA integrating auxin signaling and cold stress was also successful. So far, the targets that were planned in 2015 research year were achieved successfully. Additionally, characterization of another gene linked to endogenous auxin IBA but not IAA response is also in progress. This gene encodes a TBP-associated factor 2 (TAF2), which positively regulate the transcription from RNA polymerase II promoter. The TAF2 mutant shows abnormal cell division pattern. The functional characterization of the gene is in progress.
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