Yadav Karuna, Patel Prashanti, Srivastava Ashish Kumar, Ganapathi T R
Plant Cell Culture Technology Section, Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, India.
Plant Stress Physiology and Biotechnology Section, Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, India.
PLoS One. 2017 Nov 30;12(11):e0188933. doi: 10.1371/journal.pone.0188933. eCollection 2017.
Iron is an indispensable element for plant growth and defense and hence it is essential to improve the plant's ability to accumulate iron. Besides, it is also an important aspect for human health. In view of this, we attempted to increase the iron content in banana cultivar Rasthali using MusaFer1 as a candidate gene. Initially, the expression of all five genes of the MusaFer family (MusaFer1-5) was quantified under iron-excess and -deficient conditions. The supplementation of 250 and 350 μM iron enhanced expression of all MusaFer genes; however, MusaFer1 was increased maximally by 2- and 4- fold in leaves and roots respectively. Under iron deficient condition, all five MusaFer genes were downregulated, indicating their iron dependent regulation. In MusaFer1 overexpressing lines, iron content was increased by 2- and 3-fold in leaves and roots respectively, as compared with that of untransformed lines. The increased iron was mainly localized in the epidermal regions of petiole. The analysis of MusaFer1 promoter indicated that it might control the expression of iron metabolism related genes and also other genes of MusaFer family. MusaFer1 overexpression led to downregulated expression of MusaFer3, MusaFer4 and MusaFer5 in transgenic leaves which might be associated with the plant's compensatory mechanism in response to iron flux. Other iron metabolism genes like Ferric reductase (FRO), transporters (IRT, VIT and YSL) and chelators (NAS, DMAS and NAAT) were also differentially expressed in transgenic leaf and root, suggesting the multifaceted impact of MusaFer1 towards iron uptake and organ distribution. Additionally, MusaFer1 overexpression increased plant tolerance against methyl viologen and excess iron which was quantified in terms of photosynthetic efficiency and malondialdehyde content. Thus, the study not only broadens our understanding about iron metabolism but also highlights MusaFer1 as a suitable candidate gene for iron fortification in banana.
铁是植物生长和防御不可或缺的元素，因此提高植物积累铁的能力至关重要。此外，这对人类健康也是一个重要方面。鉴于此，我们试图利用MusaFer1作为候选基因来提高香蕉品种Rasthali的铁含量。最初，在铁过量和缺铁条件下对MusaFer家族的所有五个基因（MusaFer1 - 5）的表达进行了定量。补充250和350μM铁增强了所有MusaFer基因的表达；然而，MusaFer1在叶片和根中分别最大增加了2倍和4倍。在缺铁条件下，所有五个MusaFer基因均下调，表明它们受铁依赖性调控。在过表达MusaFer1的株系中，与未转化株系相比，叶片和根中的铁含量分别增加了2倍和3倍。增加的铁主要定位于叶柄的表皮区域。对MusaFer1启动子的分析表明，它可能控制铁代谢相关基因以及MusaFer家族的其他基因的表达。MusaFer1过表达导致转基因叶片中MusaFer3、MusaFer4和MusaFer5的表达下调，这可能与植物对铁通量的补偿机制有关。其他铁代谢基因，如铁还原酶（FRO）、转运蛋白（IRT、VIT和YSL）和螯合剂（NAS、DMAS和NAAT）在转基因叶和根中也有差异表达，表明MusaFer1对铁吸收和器官分布具有多方面的影响。此外，MusaFer1过表达提高了植物对甲基紫精和过量铁的耐受性，这通过光合效率和丙二醛含量进行了量化。因此，该研究不仅拓宽了我们对铁代谢的理解，还突出了MusaFer1作为香蕉中铁强化的合适候选基因。
