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1. 研究目的与意义、国内外研究现状（文献综述）

tomato is one of the most well known and widely used vegetables in the world. it is native to south america. it was later introduced to other regions like europe and then spread to the rest of the world. its two recognized scientific names are solanum lycopersicum and lycopersicon esculentum. tomato is a member of the family solanaceae that consist of a few economically important yields, for example, pepper, potato and eggplant. in 2017, china mainland was the top producer of tomatoes in the world with a total of 34 million tonnes of tomatoes (faostat.2017).

because they are widely grown in temperate climates, they are susceptible to biotic and abiotic stresses. biotic stresses take place as a result of other living organisms such as fungi, bacteria, viruses and harmful insects. abiotic stress on the other end include multiple stresses such as freezing, excessive light, drought, osmotic shock, salinity, wounding and uv-b irradiation. these stresses are a noteworthy reason for crop loss, reducing normal yields for most major crops by more than 50% (bray et al. 2000). salinity specifically is turning into a great global issue and influences roughly 20% of worldwide irrigated agricultural land (flowers and yeo. 1995). in china, around 100 million hectares of land, across 16 provinces have been influenced by increased salt stress (zhao et al. 2002). practically all significant crop yields, for instance, eggplant, lettuce, cabbage, potato and pepper are vulnerable to increased salinity (shannon and grieve. 1999). nac1 gene is associated with participation of both salinity and drought stress in plants.

2. 研究的基本内容和问题

the aim of this project is to clone the desirable stress tolerant genenac1in tomato, in order to characterize, describing its distinctive features.

there is not enough research done to investigate and characterize thenac1gene in tomato plant. pursuing this research will shed a lot of light on understandingnac1gene, further research can utilize the data found in this thesis paper. then the problem of abiotic stress can be easily combated, resulting in more crop production of tolerant tomatoes plants.

3. 研究的方法与方案

the process of gene cloning produces multiple identical copies of a dna molecule. the methods included in this process are:

1.extraction of rna - to obtain rna, a tomato plant tissue is homogenized in a mortar containing liquid nitrogen. the use of trizol helps with maintaining the integrity of rna during tissue homogenization, and simultaneously disrupts cell components. chloroform is used to ensure a clear distinction between the liquid phase and organic phase after centrifugation. the upper aqueous layer that contains rna is removed from the solution to obtain the rna sample. isopropanol is used to dissolve any salts that might have chelated to the rna samples. then, purity analysis of total rna are made using ultraviolet spectroscopy and a gel electrophoresis is performed.

2.reverse transcription – is a process that synthesis complementary dna from a single stranded rna template. in this experiment we will be using the obtained total rna that was extracted. this process is a simple step of adding all the necessary components in a tube before incubating it in high temperature. reverse transcriptase, also known as rna-directed dna polymerase is an important enzyme encoded from the genetic material of retroviruses that catalyzes the transcription of retrovirus rna (ribonucleic acid) into dna(deoxyribonucleic acid).

4. 研究创新点

TheNAC1gene as part of the NAC family of genes plays key roles in plants such as plant development, transcription regulation and regulatory pathways involving protein-protein interactions.It also plays a significant role in biotic and abiotic stress responses.These observations have been made asNAC1gene responds to stress stimuli and enhanced stress tolerance in transgenic plants over-expressing it.

5. 研究计划与进展

25/02/2019–01/03/2019: find journals online to use to search for relevant scientific papers that i will need to read for my thesis work.

04/03/2019: find journals online to use to search for relevant scientific papers that i will need to read for my thesis work.

05/03/2019–09/03/2019:write thesis proposal