Salt cress. A halophyte and cryophyte Arabidopsis relative model system and its applicability to molecular genetic analyses of growth and development of extremophiles
Salt cress. A halophyte and cryophyte Arabidopsis relative model system and its applicability to molecular genetic analyses of growth and development of extremophiles
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DOI：
10.1104/pp.104.041723
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发表时间：
2004-07-01
期刊：
影响因子：
7.4
通讯作者：
Zhu, JK
中科院分区：
文献类型：
--
作者：
Inan, G;Zhang, Q;Zhu, JK
盐芥（Thellungiella halophila）是一种小型的冬季一年生十字花科植物，生活史短。它具有小的基因组（约2 ×拟南芥），与拟南芥具有高序列同一性（平均92%），并且可以通过简单的花浸程序进行遗传转化。它能够产生大量的种子。盐芥是一种原生于恶劣环境的极端微生物，在极端盐度（500毫米NaCl）或-15摄氏度的低温下可以繁殖。它是一种典型的盐生植物，在暴露于高盐度期间以受控的速率积累NaCl，并且也积累显著水平的Pro（>150 mm）。盐芥的气孔密度较高，但比拟南芥的气孔开放度低，对盐胁迫的响应是关闭得更紧。盐水芹的叶子更像肉质的，有第二层栅栏叶肉细胞，在极端的盐胁迫下经常脱落。与拟南芥相比，盐芥的根发育了额外的内皮层和皮层细胞层。盐芥虽然耐盐耐寒，但对土壤干燥的耐受性并不特别好。我们已经分离出几个乙基甲基磺酸盐突变体的盐水芹，降低耐盐性，这提供了证据表明，在这种盐生植物的耐盐性可以显着影响个别的遗传位点。盐芥表达的序列标签的分析提供了证据的旁系同源物的存在下，在拟南芥基因组中的缺失，并与非生物胁迫相关的功能的基因。杂交的盐水芹RNA目标的拟南芥全基因组寡核苷酸阵列表明，通常应力相关的转录本在一个显着的更高的水平在非应力盐水芹植物的表达，并迅速诱导应力下。盐芥的有效转化允许拟南芥和盐芥之间的简单基因交换。此外，已经在进行中的T-DNA标记的盐芥突变体集合的产生，将打开一个新时代的极端微生物植物生物学正向和反向遗传研究的大门。
Salt cress (Thellungiella halophila) is a small winter annual crucifer with a short life cycle. It has a small genome (about 2 x Arabidopsis) with high sequence identity (average 92%) with Arabidopsis, and can be genetically transformed by the simple floral dip procedure. It is capable of copious seed production. Salt cress is an extremophile native to harsh environments and can reproduce after exposure to extreme salinity (500 mm NaCl) or cold to -15degreesC. It is a typical halophyte that accumulates NaCl at controlled rates and also dramatic levels of Pro (>150 mm) during exposure to high salinity. Stomata of salt cress are distributed on the leaf surface at higher density, but are less open than the stomata of Arabidopsis and respond to salt stress by closing more tightly. Leaves of salt cress are more succulent-like, have a second layer of palisade mesophyll cells, and are frequently shed during extreme salt stress. Roots of salt cress develop both an extra endodermis and cortex cell layer compared to Arabidopsis. Salt cress, although salt and cold tolerant, is not exceptionally tolerant of soil desiccation. We have isolated several ethyl methanesulfonate mutants of salt cress that have reduced salinity tolerance, which provide evidence that salt tolerance in this halophyte can be significantly affected by individual genetic loci. Analysis of salt cress expressed sequence tags provides evidence for the presence of paralogs, missing in the Arabidopsis genome, and for genes with abiotic stress-relevant functions. Hybridizations of salt cress RNA targets to an Arabidopsis whole-genome oligonucleotide array indicate that commonly stress-associated transcripts are expressed at a noticeably higher level in unstressed salt cress plants and are induced rapidly under stress. Efficient transformation of salt cress allows for simple gene exchange between Arabidopsis and salt cress. In addition, the generation of T-DNA-tagged mutant collections of salt cress, already in progress, will open the door to a new era of forward and reverse genetic studies of extremophile plant biology.