آنالیز بیان پیشبر ژن CaDRRG از منشاء نخود، در پاسخ به هورمون های دفاعی گیاه و عصاره قارچ Ascochyta rabiei در لاین های تراریخت توتون

Ascochyta blight is one of the most common destructive diseases in most areas under chickpea cultivation. The fungus that causes this disease in asexual form named Ascochyta rabiei, has made it difficult to produce stable resistant chickpea cultivars due to its high diversity and the frequency of numerous mutations. Understanding the molecular mechanism of pathogenicity of this fungus during interaction with chickpea genotypes has made it possible to rely on new genetic manipulation technologies to produce stable resistant cultivars by transferring appropriate resistance genes. The selection of the appropriate resistant gene in order to transfer to high-yielding chickpea genotypes will require a regulatory sequence that can express the appropriate amount of the resistance gene product at the suitable time and place in the plant. Isolation and analysis of upstream regulatory sequences of early responsive genes to A. rabiei at early times can be very valuable for chickpea breeding programs. In past studies, the isolation and expression analysis of the upstream regulatory sequence of the CaDRRG gene in the conditions of Agarbacterium based transient expression in the model plant has shown promising results in the inducibility of this regulatory sequence in response to defense hormones and also treatment by fungal extract of A. rabiei isolates. Transferring the ProCaDRRG::GUSi cassette and producing transgenic lines for further analysis of this regulatory sequence has also been accomplished in previous studies. In the present study, by confirming the transgenic lines and their molecular analysis, the performance of nine transgenic tobacco lines harboring the ProCaDRRG::GUSi cassette and one transgenic tobacco line harboring the ProCaMV 35S::GUSi cassette as positive contorol have been investigated in response to the defense hormones salicylic acid and methyl jasmonate, and also treatment by fungal extract and direct inoculation by A. rabiei pathotypes. The results of this study showed that the qualitative expression caused by beta-glucuronidase enzyme activity in transgenic tobacco plants harboring ProCaDRRG::GUSi cassette in non-induction conditions is very low compared to transgenic tobacco plants harboring ProCaMV 35S::GUSi cassette, which indicates the low basal expression of this regulatory sequence in non-induction conditions. The inducibility of the ProCaDRRG::GUSi cassette was confirmed under induction conditions by salicylic acid and methyl jasmonate hormones and showed that this regulatory sequence is able to respond in the defense pathways of these hormones. Conducting additional studies to quantitatively evaluate the inducibility of this regulatory sequence can be used in breeding programs to produce resistant transgenic chickpea cultivars.