Chapter 7 Genetic Characteristics and Improvement
of Plant Nutrition
[目的与要求]
1．掌握关于植物营养遗传方面的几个基本概念;
2．了解提高植物营养效率的遗传学途径.
3. 了解植物营养遗传学的研究内容、方法及技术
[重点]
植物营养遗传学的概念及其研究方法
[难点]
植物营养遗传改良的基因工程技术
[课堂组织]
讲述、讨论和多媒体教具结合
[教学内容]
7.1 General
Genetics Plant Nutrition （植物营养遗传学）is an inevitable choice of plant nutrition development or sustainable agriculture in the world.
Molecular Biology of Plant Nutrition
High-input Approach of Agricultural Production
Soil fertility factors were adjusted to optimum levels for a given plant species.
Problems of High-input Approach
1） ore resources
Estimate: world reserves of P ores are quite adequate to supply demands for only 50 years
2） Energy
Agriculture production consumed more than 6×106 ton of petroleum, 8 ×105 ton of steel, 1.6 ×104 ton of rubber in 1980’s in America, world.
3） Environment
Deterioration in land quality, pollution.
Low-input Approach of Agricultural Production
Plants adapted to given ecological conditions
Selecting or breeding genotypes with high nutrient efficiency and high tolerance!!
Possibility of Low-input Approach
1） Nutrient reserves for plant growth
The average reserves of N, P and K are 500~10000 kg, 2500~20000kg and 25000 ~250000 kg, respectively, in the cultivated horizon in China, which could supply N, P, K nutrition for 20~45, 25~200 and 133~13330 years according to the agricultural production.
2） Genetic potential for plants to adapt stress environment
Genetics of Plant Nutrition is an inevitable choice of plant nutrition development.Genetics of Plant Nutrition (植物营养遗传学) is a science using genetics theory and molecular biological technology to improve nutrition character of plant，which includes high efficiency utilization to nutrients and high resistance to stress environments.
7.2 Several Concepts on Plant Nutrition Efficiency
7.2.1 Nutrient efficiency （养分效率）
Capacity of a given genotype to gain highest yield or nutrient content at a given nutrient condition.
Capacity of a given genotype to gain more higher yield than standard genotype at the condition of nutrient deficiency.
Gene potential of a given genotype to gain higher yield at nutrient deficiency.
Nutrient efficiency （养分效率）：Including two aspect meanings:
1）. Capacity of a high efficiency genotype to grow normally at low level of available nutrients which can not satisfy the demand for most plants to grow normally.
2）.Gene potential of a high efficiency genotype to increase yield with the increase of available nutrients at the substance.
7.2.2 Uptake efficiency （吸收效率）：
Capacity for plants to absorb nutrient at the condition of nutrient deficiency
Affecting factors (Root morphology) :
1)Root space structure
2)Root volume
3)Root length
4)Root density
5)Root hair
6)Mycorrhizas Infection
7)Capacity to regulate Rhizosphere’s physical, chemical and biological characteristics
7.2.3 Transport efficiency （运输效率）：
Capacity for plants to transport nutrient from root to metabolizing site by short/long distance transport.
7.2.4 Utilization efficiency （利用效率）：
Shoot dry matter weight per unit of absorbed nutrient.
图7-1 植物营养效率图
7.3 Techniques of Genetic Improvement for Plant Nutrition
7.3.1 Research Techniques of Plant Nutrition Genetics
7.3.1.1 Mutant（突变体） application
Fig. 7－2 Positional cloning of BOR1 gene
7.3.1.2 Molecular Marker(分子标记) Application
Restriction fragment length polymorphism (限制性片段长度多态性, RFLP)
Random Amplified polymorphism DNA (随机扩增多态性DNA, RAPD)
Simple Sequence Repeat (简单重复序列，SSR)
Amplified fragment length polymorphism (扩增片段长度多态性, AFLP)
Single nucleotide polymorphism(单核苷酸多态性，SNP)
Restriction Fragment Length Polymorphism (限制性片段长度多态性, RFLP)
Fig. 7－3 Interval marker of significant-effected QTL on boron efficiency
and other agronomic traits
7.3.1.3 mRNA差异显示（mRNA differential display）
所有的生物体都有成千上万的独特基因，它们当中只有一部分（可能是15%）能在任何细胞中表达。因此，决定生命进程的细胞表达受时间和空间限制。
mRNA差异显示技术是通过mRNA 3‘末端系统化扩增和DNA测序凝胶片段分离进行工作的。利用设计好的与POLY-A尾部的5’界面结合的锚式探针进行逆转录，接着用任意顺序的附加上游探针进行PCR 扩增，通过变性聚丙烯酰胺电泳被显示出来。
这个方法可以将正常和胁迫条件下细胞中的绝大多数mRNA 进行直接比较所表达基因。从而达到分离和克隆组织或发育特异表达的基因。
7.3.1.4 Application of Biochip (生物芯片)
Gene chip (基因芯片) 、 DNA chip ( DNA芯片）、 DNA microarrays （ DNA微探针阵列）、 oligonucleotide microchip（寡核苷酸芯片）and so on
DNA芯片是指采用原位合成或直接点样的方法将DNA片段或寡核苷酸片段排列在硅片、玻璃等介质上形成微短阵，待校样品用荧光分子标记后，与微短阵杂交，通过荧光扫描及计算机分析即可获得样品中大量的基因序列及表达信息，以达到快速、高效、高通量地分析生物信息的目的的一种研究手段。
目前，广泛应用的主要有2类DNA芯片。
（1）原位合成的寡核苷酸芯片。
（2）合成后点样得到的cDNA芯片。
 |
图7-4 生物芯片图
7.3.1.5 Application of Reverse Genetics (反向遗传学)
DNA sequence protein sequence gene
“Regular”genetics
mutant phenotype
Character ← Gene (DNA) ← Protein
Reverse genetics is becoming significant as data accumulate in whole genome-sequencing projects
7.3.1.6 Culture and Selection of Plant Organ, Tissue and Cell
Totipotency (全能性) of plant cell
Selecting nutrient efficiency genotype from the regeneration plant by excised culture techniques
7.3.2 Improvement technique of plant nutrition genetic character
7.3.2.1 Routine Breeding
Introduction and domestication (引种和驯化)
Population selection (群体选择)
Breeding by hybridization (杂交育种)
Mutation breeding (诱变育种)
7.3.2.2 Cell genetics Pathway
Chromosome doubling (染色体数加倍)
Chromosome substitution and appending (替换和添加)
Admitting of heterogenous chromosome fragment (外源染色体片段导入)
7.3.2.2 Somatic genetics Pathway
Callus (愈伤组织培养)
Organ culture (器官培养)
Cell culture (细胞培养)
Protoplasm (原生质体培养)
7.3.2.4 Plant genetic engineering (植物遗传工程)
In general, it includes gene engineering , cell engineering，
Gene engineering
It is mainly recombinant DNA technology, which includes:
（1）Cloning gene of interest
（2）Constructing recombinant DNA molecule
（3）Transgenic technology and Expression of cloned DNA
Genetics of Plant Nutrition (植物营养遗传学) is a science using genetics theory and molecular biological technology to improve nutrition character of plant，which includes high efficiency utilization to nutrients and high resistance to stress environments.
[复习题]
1 名词解释：植物营养遗传学，营养效率，吸收效率，利用效率，基因，表现型，基因型，反向遗传学
2 如何理解农业生产的高投入和低投入途径？
3 什么是植物营养遗传学？试分析目前植物营养遗传学发展的必要性和可能性
4 植物营养性状遗传改良的主要途径