| Most of China's mainland is the East Asian monsoon region,and the climate is relatively complicated due to the influence of the monsoon.With the rapid increase in water consumption for industry,urban life and agriculture,coupled with the deterioration of the global water environment,the groundwater table has fallen,resulting in frequent droughts in China.Brassica napus(Brassica napus L.)is currently the main type of rape planted in China.It has the advantages of high yield and resistance to diseases and insect pests,but its resistance to drought and barrenness is relatively poor.Moisture has an important influence on the growth and yield of rape.Water shortage will have a lot of adverse effects on rape,directly affecting the morphology of rape and the final yield formation,which in turn restricts the expansion of rapeseed planting area and the development of rapeseed industry.Therefore,the research on drought tolerance of rapeseed is a very important and urgent task.This study mainly from the four aspects of identification and screening of drought resistance germplasm,analysis of agronomic traits and physiological indicators related to drought resistance,transcriptome analysis of drought resistance genes and expression analysis of related genes,the following main research results were obtained.1.120 Brassica napus germplasms were selected,and the drought resistance identification of the test materials at the leaf seedling stage was carried out by PEG simulated drought method.The drought resistance morphological identification and classification of the test materials and the drought resistance index analysis results showed that the drought resistance among different germplasms Sexual differences are obvious;cluster analysis divides 120 materials into 5 types of resistance,high resistance,medium resistance,low resistance,low sensitivity,and high resistance.In the end,6 high-resistance materials and 39 high-sensitivity materials were selected,which provided a material basis for subsequent research.Seven physiological indexes such as water retention capacity,soluble protein and proline content of leaves before and after treatment were measured and analyzed using the PEG simulated drought method at the 3-5 leaf stage of the above 120 Brassica napus.The results showed that the leaf water retention capacity,malondialdehyde content,soluble protein,and soluble sugar were significantly different after treatment.After correlation analysis,principal component analysis,and path analysis,the results showed that malondialdehyde content,soluble protein,proline,and cabbage The drought resistance of type rape is closely related.Therefore,these indicators can be used as auxiliary physiological indicators for early screening of drought-resistant materials.2.The 120 Brassica napus identified in the previous period were used as the test material,using natural field drought treatment(no irrigation),the control was normal irrigation,and the drought resistance was investigated and identified(7-10 leaf stage),and its solubility was sampled The physiological indexes such as protein,malondialdehyde and proline were measured and analyzed,and the agronomic traits such as plant height,main inflorescence length,number of branches at one time,number of main axis angle fruits and yield per plant were controlled by drought treatment at the mature stage and the control group.Field investigation and seed testing revealed that after drought stress,the plant height,main inflorescence length,number of branches per branch and yield per plant were correspondingly reduced,and its physiological indicators were relatively increased.After analysis,it was found that its physiological response was more agronomic The traits are more obvious,and the correlation with drought resistance is also more significant,so when evaluating drought resistance,physiological indicators should be preferred for identification.3.Drought resistance material 2351 and sensitive drought material 899 were selected as test materials,and PEG simulated drought method was used to perform 48 h drought treatment at the 4-5 leaf stage of their growth.The transcriptome sequencing was performed before and after the treatment of the two materials.After conducting GO and KEGG analysis,seven genes related to drought resistance in Brassica napus were finally identified: Bna A05g27660 D,Bna C08g23920 D,Bna A01g31910 D,Bna A06g39340 D,Bna A01g28540 D,Bna C04g29320 D,Bna Anng20780D;sequencing results showed that q RT-PCR confirmed the sequencing results.The results are consistent with the trend of q RT-PCR results,and the sequencing results are true and reliable.4.The drought-resistant material 2351 and the sensitive drought material 899 were used as test materials,and the PEG simulated drought method was used to perform drought treatment.The 7 genes excavated by transcriptome sequencing were used as candidate genes.The expression levels in the roots and leaves of the materials showed that the expression levels of Bna A05g27660 D,Bna A06g39340 D,and Bna A01g31910 D changed significantly with the extension of the treatment time,and the expression differences between drought-resistant and sensitive drought materials were large,so these three The gene is used as a candidate gene for the next relevant experiment. |
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