Naveed Ur Rehman1, Farhat Abbas2, Muhammad Imran3, Intikhab Alam1, Muhammad Imran3, Ihteram Ullah4, Muhammad Riaz5, Fahim Ullah Khan6. 1. State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Agriculture, South China Agricultural University, Guangzhou, 510642, China. 2. The Research Center for Ornamental Plants, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China. 3. College of Resources and Environment, Huazhong Agricultural University, Wuhan, China. 4. Department of Plant Breeding & Genetics, Gomal University, Dera Ismail Khan, Pakistan. 5. State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresource, Root Biology Center, College of Natural Resource and Environment, South China Agricultural University, Guangzhou, China. 6. Department of Agriculture, Hazara University, Mansehra, Pakistan. fahimbiotech@gmail.com.
Abstract
BACKGROUND: Strigolactones (SLs) are newly identified hormones and their biosynthesis is stimulated under phosphate deprivation and accomplished by the action of several enzymes, including the beta-carotene isomerase DWARF27 (D27). Expression of D27 is well renowned to respond to phosphate insufficiency. However, the identification and functional analysis of the carotenoid isomerase D27 genes are not elucidated in soybean. METHODS AND RESULTS: A total of six D27 genes were identified in the soybean genome and designated on the basis of chromosomal localization. According to the findings, these genes were irregularly distributed on chromosomes, and segmental repetition led to the expansion of the soybean GmD27 gene family. Based on a neighbor-joining phylogenetic tree, the predicted D27 proteins of soybean were divided into three clades. Based on RNA seq data analysis, GmD27 genes were differently expressed in various tissues but GmD27c was the highest. Therefore, GmD27c was chosen for the additional functional study due to its rather obvious transcription in nodulation and roots. RT-qPCR results showed that GmD27c was highly expressed in different nodule stages and in response to rhizobia infection. Functional characterization of GmD27c revealed that overexpression of GmD27c led to higher nodule number, while GmD27c knockdown caused fewer nodules compared to GUS control. Furthermore, GmD27c overexpressed and knockdown lines oppositely regulated the expression of numerous nodulation genes, which are vital for the development of nodules. CONCLUSION: This study not only discovered that SL biosynthesis and signaling pathway genes are conserved, but it also revealed that SL biosynthesis gene GmD27c and legume rhizobia have close interactions in controlling plant nodule number.
BACKGROUND: Strigolactones (SLs) are newly identified hormones and their biosynthesis is stimulated under phosphate deprivation and accomplished by the action of several enzymes, including the beta-carotene isomerase DWARF27 (D27). Expression of D27 is well renowned to respond to phosphate insufficiency. However, the identification and functional analysis of the carotenoid isomerase D27 genes are not elucidated in soybean. METHODS AND RESULTS: A total of six D27 genes were identified in the soybean genome and designated on the basis of chromosomal localization. According to the findings, these genes were irregularly distributed on chromosomes, and segmental repetition led to the expansion of the soybean GmD27 gene family. Based on a neighbor-joining phylogenetic tree, the predicted D27 proteins of soybean were divided into three clades. Based on RNA seq data analysis, GmD27 genes were differently expressed in various tissues but GmD27c was the highest. Therefore, GmD27c was chosen for the additional functional study due to its rather obvious transcription in nodulation and roots. RT-qPCR results showed that GmD27c was highly expressed in different nodule stages and in response to rhizobia infection. Functional characterization of GmD27c revealed that overexpression of GmD27c led to higher nodule number, while GmD27c knockdown caused fewer nodules compared to GUS control. Furthermore, GmD27c overexpressed and knockdown lines oppositely regulated the expression of numerous nodulation genes, which are vital for the development of nodules. CONCLUSION: This study not only discovered that SL biosynthesis and signaling pathway genes are conserved, but it also revealed that SL biosynthesis gene GmD27c and legume rhizobia have close interactions in controlling plant nodule number.
Authors: Joanne L Simons; Carolyn A Napoli; Bart J Janssen; Kim M Plummer; Kimberley C Snowden Journal: Plant Physiol Date: 2006-12-08 Impact factor: 8.340