The Analysis Of Cell Architecture, MRNA Differential Display And BADH Sequences Of Different Salt-tolerant Varieties In Cotton

For different salt-tolerant varieties-ZHM3, LM6, LMY15, 91011 and 91015, We analyzed the difference of cell architecture and DNA degradation, mRNA differential display and the difference of BADH sequences under salt-stress condition, respectively by microscope, DD-PCR and the combination PCR and DNA sequence analysis. The main results were as follows:1. Through cell architecture changes under salt-stress conditions, we found out the reactive relation of different materials. Under 0.1% NaCl, their cell architecture are normal. Under 0.2% and 0.5%, comparing with that ofsalt-sensitive material-LM6, phloem and xylem of salt-tolerant material-ZHM3 are injured less serious. But the injury is more and more serious with the increasing of salt concentration for both ZHM3 and LM6.2. DNA damage after 12h and 24h under 0.5% NaCl shows that salt stress can cause PCD in cotton. PCD can be stated by DNA degradation as follows: All materials don't happen DNA degradation under low salt concentration. Salt-tolerant materials have less serious DNA degradation than salt-sensitive materials under salt-tolerant concentration. And DNA degradation of all materials become more and more serious with a long time treat.3. We extract mRNA of LM6 and 91011 dealt with 6% NaCl and anti-transcript to cDNA. 432 fragments were appeared with 60 primers in this test. Among these primers, 52 primers revealed no difference. Two primers-OPD05 and OPF11 amplified zero specific fragment. 6 primers amplified 9 specific fragments that appeared in 91011 but not in LM6. These 9 fragments are expressed under salt stress, so they can be related to salt-tolerance, but which must be testified.4. We quest the nucleotide sequences of BADH gene in plants from Genbank. , EMBL and NCBI. Compare their homology by DNAsis and blast2 and find out its conservative nucleotide sequence, then design a couple of primers and PCR in different tested materials. The amplified results are different. The specific fragments amplified by LMY15, 91011, 91015, ZHM 3 and LM6 were 1, 3, 3, 2 and 2, respectively. Sequence analysis of 1000bp-2000bp from ZHM 3 and LM 6 stated that the homology was 97%. So they were the same gene fragment. Blast stated that it had high homology with BADH of other plants. From the nucleotide, we deduced the amino acid sequence, which has high homology with that of BADH from other plants too. Henceforth, this specific fragment is BADH fragment in cotton, but materials with BADH needn't have high salt tolerance. We included that BADH wasn't the main salt-tolerant gene in cotton.