Sujatha M, Reddy T P, Mahasi M J
Directorate of Oilseeds Research, Rajendranagar, Hyderabad, India.
Biotechnol Adv. 2008 Sep-Oct;26(5):424-35. doi: 10.1016/j.biotechadv.2008.05.004. Epub 2008 May 22.
Castor and Jatropha belong to the Euphorbiaceae family. This review highlights the role of biotechnological tools in the genetic improvement of castor and jatropha. Castor is monotypic and breeding programmes have mostly relied on the variability available in the primary gene pool. The major constraints limiting profitable cultivation are: vulnerability to insect pests and diseases, and the press cake is toxic which restrict its use as cattle feed. Conventional breeding techniques have limited scope in improvement of resistance to biotic stresses and in quality improvement owing to low genetic variability for these traits. Genetic diversity was assessed using protein based markers while use of molecular markers is at infancy. In vitro studies in castor have been successful in shoot proliferation from meristematic explants, but not callus-mediated regeneration. Genetic transformation experiments have been initiated for development of insect resistant and ricin-free transgenics with very low transformation frequency. In tropical and subtropical countries jatropha is viewed as a potential biofuel crop. The limitations in available germplasm include; lack of knowledge of the genetic base, poor yields, low genetic diversity and vulnerability to a wide array of insects and diseases. Great scope exists for genetic improvement through conventional methods, induced mutations, interspecific hybridization and genetic transformation. Reliable and highly efficient tissue culture protocols for direct and callus-mediated shoot regeneration and somatic embryogenesis are established for jatropha which indicates potential for widening the genetic base through biotechnological tools. Assessment of genetic diversity using molecular markers disclosed low interaccessional variability in local Jatropha curcas germplasm. The current status and future prospects of in vitro regeneration, genetic transformation and the role of molecular tools in the genetic enhancement of the two-oilseed crops are discussed.
蓖麻和麻风树属于大戟科。本综述重点介绍了生物技术工具在蓖麻和麻风树遗传改良中的作用。蓖麻是单型的，育种计划大多依赖于初级基因库中存在的变异性。限制其盈利种植的主要因素包括：易受病虫害侵袭，且榨油后的饼粕有毒，限制了其作为牛饲料的用途。由于这些性状的遗传变异性低，传统育种技术在提高对生物胁迫的抗性和品质改良方面的作用有限。基于蛋白质的标记用于评估遗传多样性，而分子标记的应用尚处于起步阶段。蓖麻的离体研究已成功地从分生组织外植体增殖出芽，但未实现愈伤组织介导的再生。已经开展了遗传转化实验，以培育抗虫和无蓖麻毒素的转基因植株，但其转化频率非常低。在热带和亚热带国家，麻风树被视为一种潜在的生物燃料作物。现有种质资源的局限性包括：对遗传基础缺乏了解、产量低、遗传多样性差以及易受多种病虫害侵袭。通过常规方法、诱导突变、种间杂交和遗传转化进行遗传改良的潜力很大。已经建立了可靠且高效的麻风树组织培养方案，用于直接和愈伤组织介导的芽再生以及体细胞胚胎发生，这表明通过生物技术工具拓宽遗传基础具有潜力。利用分子标记评估遗传多样性发现，当地麻风树种质的种间变异性较低。本文讨论了这两种油料作物离体再生、遗传转化的现状和未来前景，以及分子工具在其遗传改良中的作用。
