The expression of cold resistance genes in wheat cultivars

Van der Walt, Cornelia ; ["Labuschagne, M. T.","Maartens, H."]

University of the Free State

Others  :  http://scholar.ufs.ac.za/xmlui/bitstream/11660/8294/1/VanderWaltC.pdf

瑞士|英语

来源: University of Iowa

【 摘 要 】

English: Cultivars produce proteins in their normal life cycle. Some of these proteins are produced ingreater quantities in reaction to cold temperatures in certain cultivars. In this study, 27 wheatcutivars were tested for their protein composition. The proteins produced could be divided into 14different groups with each group having a certain molecular weight range. These groups werethe same for the proteins in the coleoptiles and roots of wheat cultivars.Cold susceptible and tolerant cultivars were compared with each other to evaluate theirdifferences in response to cold. The following was found:In the coleoptiles, the tolerant cultivars gained bands across the 14 groups in reaction to coldtemperatures. This was also found in the roots of tolerant cultivars. Two of the susceptiblecultivars tested (Adam Tas and SST 66), lost more bands in their coleoptiles across the differentgroups than they gained. The other two susceptible cultivars tested (Palmiet and Snack) gainedmore bands than they had lost. All the susceptible cultivars (except Palmiet) gained more bandsin their roots in response to cold hardening. Palmiet gained and lost the same number of bands.Most cultivars produced more proteins in response to cold.Although proteins are produced in response to cold, not all the cultivars were able to produce thenecessary proteins to make them more tolerant to cold. It was clear that some proteins wereproduced more in all or most cultivars in reaction to cold, but the susceptible and tolerant cultiavrsproduced different proteins. In the coleoptiles, the susceptible cultivars had no change or gainedbands in group 3 and group 11 while the tolerant cultivars had no change or lost bands in thesegroups. The susceptible cultivars lost bands (or there were no change in the number of bandsproduced) in group 4, group 10, group 12 and group 14. The tolerant cultivars gained bands inthese groups in response to cold. In the roots, the susceptible cultivars gained bands (or therewere no change in the number of bands produced) in group 5, group 11 and group 14. The coldtolerant cultivars lost bands in these groups. Only in group 2, did the cold susceptible cultivarslose bands, while the tolerant cultivars gained bands. The tolerant cultivars thus gained bands intheir coleoptiles, whiel they produced fewer proteins in their roots in response to coldtemperatures. The susceptible cultivars, however, produced more proteins in their roots than intheir coleoptiles in response to cold. Jacobs (1999) found that some cultivars are susceptible tocold in their coleoptiles, but they are tolerant in their roots. SST 66 is an example of a cultivarsthat is susceptible to cold in its coleoptiles, but it is tolerant to cold in its roots. If one looks at SST 66, it is seen that this cultivars does not produce proteins in reaction to cold temperatures, thusreacting like a susceptible cultivar in its coleoptiles and like a tolerant cultivar in its roots.The susceptible cultivars produced more dark bands in their roots. Thus, the intensity of proteinsincreased in the roots of susceptible cultivars. In tolerant cultivars however, the intensity ofproteins increased in the coleoptiles. Tolerant cultivars produced three times more dark bands intheir coleoptiles than susceptible cultivars.If one looks at the production of certain groups, it is found that more proteins were produced inthe coleoptiles of susceptible cultivars in group 6, group 8, group 9, group 10 and group 13. Onlygroup 13 was produced in greater amounts in susceptible cultivars and not in the tolerantcultivars. In the coleoptiles of the tolerant cultivars, group 5 and group 7 were produced ingreater amounts. It is however, not present in high amounts in susceptible cultivars. In the rootsof cultivars, group 3, group 4, group 5 and group 9 can be correlated with cold temperature as it isproduced in greater amounts in both the susceptible and tolerant cultivars. A higher intensity ofproteins in group 6, group 13 and group 14 are correlated with susceptibility to cold, as it was onlydetected in susceptible cultivars. Tolerant cultivars produced these proteins in normal or lowamounts in response to cold temperatures.Thus, the proteins with molecular weights of 54,5 - 50 kDa (group 5) and 43.5 - 39 kDa (group 7)could be used to screen for tolerance to cold in the coleoptiles of wheat cultivars, while theproteins with molecular weight of 60 - 55.5 kDa (group 4), 43.5 - 39 kDa (group 7) and 27 - 22.5kDa (group 10) could be used to screen for tolerance to cold in the roots of wheat cultivars. It isfurther recommended that breeders discard any lines that show an increase in the production ofproteins in their roots in the range of 49 - 44.5 kDa (group 6), 10. 5 - 6 kDa (group 13) and 5 - 0kDa (group 14).