بررسي عملكرد ژن OsVPI ﴿رمزده يك عامل رونويسي دخيل در ترارساني پيام ABA﴾ از طريق مطالعه لاين هاي جهش يافته برنج

چكيده انگليسي :

Functional Analysis of OsVP1 Encoding a Transcription Factor Involved in ABA Signal Transduction Using Rice Mutant Lines Fateme Hashemi fatemehashemi1363@yahoo com Date of Submission 05 04 20011 Department of Agronomy and Plant Breeding Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Mohammad Mahdi Majidi majidi@cc iut ac ir Supervisor Zahra Sadat Shobbar shobbarz@yahoo com Abstract ABA Insensitive3 Viviparous1 ABI3 VP1 genes encode transcription factors are involved in ABA signal transduction The viviparous 1 vp1 gene in maize controls multiple developmental responses associated with the maturation phase of seed formation Null alleles of ABI3 and VP1 result in loss of ABA sensitivity leading to non dormancy or vivipary in Arabidopsis and maize respectively In Arabidopsis plants ABI3 is the regulator of a large number of ABA responsive genes In abi3 mutants seed development and germination is disturbed due to reduced sensitivity to ABA In rice OsVP1 is theortholog of the maize VIVIPAROUS 1 VP1 and arabidopsis ABI3 OsVP1 gene expression is increased significantly by drought stress and abscisic acid The objective of this research is the functional analysis of OsVP1 gene in rice through studying related mutant lines Therefore characteristics of the mutants T DNA inserted lines in the promoter or coding region of OsVP1 gene and wild type rice plants were comparedin vegetative and reproductive stages to clarify the role of this gene As well the comparative analysis of the wild and mutant lines T DNA inserted in the promoter of OsVP1 gene response to abscisic acid treatment and abiotic stresses were done in addition to the expression analysis of OsVP1 gene and the candidate downstream genes in 12 day seedling using real time PCR Mutant plants in OsVP1 coding region were pale subtle and short compared to the wild type in both vegetative and reproductive growth stages No yield was achieved by the mutant plants as the florets contained poor crouch and colorless anthers Second Leaf and panicle length as well as plant height of mutants in OsVP1 promoter region were less than the wild type Panicle emergence and grain filling were also delayed compared to the wild type Abiotic stress induced growth reduction was observed in seedlings of both wild type and mutant plants Gene expression analysis were revealed that OsVP1 transcripts levels have been increased under drought salinity cold and ABA treatments compared to the control condition Also OsVP1 has up regulated considerably in mutant plant in OsVP1 promoter region which were expected because the T DNA inserion carries several enhancers from 35S promoter of cauliflower mosaic virus Based on the literature ABI3 VP1 as a transcription factor can act both as an activator and a repressor depending on the promoter context of the downstream genes in ABA signal transduction pathway According to the achieved results in the present research increased OsVP1 transcript levels under abiotic stress condition up regulated OsEm a LEA gene expression considerably while no significant difference were detected under control condition This result may suggest for the requirement of both OsVP1 and ABA for OsEM upregulation Decreased level of OsCesA4 a cellulose synthase catalytic subunit encoding gene was also observed in the mutants T DNA inserted in the promoter of OsVP1 gene in all the studied conditions suggesting that OsVP1 plays a role in the OsCesA4 gene downregulation Key Words ABA Absicic acid insensitive rice Oryza sativa abiotic stress mutant OsVP1 oryza sativa viviparous OsVP1 downstream genes

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بررسي عملكرد ژن OsVPI ﴿رمزده يك عامل رونويسي دخيل در ترارساني پيام ABA﴾ از طريق مطالعه لاين هاي جهش يافته برنج

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