Bph14 is a gene conferring resistance to Brown planthopper (BPH) at seedling and maturity stages of the rice plant.
Bph14 was first mapped from the introgression line B5, derived from O. officinalis, with Qbp1 (renamed as Bph14) on chromosome 3 explaining 26.4% of the phenotypic variance of BPH resistance in this population. Bph14 encodes a coiled-coil, nucleotide-binding, and leucine-rich repeat (CC-NB-LRR) protein. Sequence comparison indicates that Bph14 carries a unique LRR domain that might function in recognition of the BPH insect invasion and activating the defense response. Bph14 is predominantly expressed in vascular bundles, the site of BPH feeding. Expression of Bph14 activates the salicylic acid signalling pathway and induces callose deposition in phloem cells and trypsin inhibitor production after planthopper infestation, thus shows antibiosis and antixenosis effects on BPH, like delaying the development of males and decreasing the female ratio and copulation rate, as well as the antixenosis action against BPH nymphs, female adults and ovipositon, and what's more, some P450 members of the CYP4 and CYP6 family in BPH are inducible by host allelochemicals, like CYP6AX1, CYP6AY1, CYP4C61, CYP4C62, CYP6CS1, CYP6CW1 and CYP303A1. Bph14 showed a stable resistance in different genetic backgrounds and thus is valuable in development of resistant rice varieties.
GO assignment(s): GO:0009625
Bph14 is expressed constitutively in leaf sheaths, leaf blades, and roots. Bph14 activity was examined using transgenic plants carrying the fusion construct of the Bph14 promoter region and the GUS reporter gene. The expression of GUS in transgenic plants was detected mainly in the vascular tissue of various organs, including leaf sheaths and leaf blades. In cross-sections of these organs, GUS activity was strongly detected in the parenchyma cells bordering xylem vessels and sieve tubes. Such an expression pattern is consistent with the role of Bph14 in recognizing BPH attack in phloem cells.
|Primer||Forward primer||Reverse primer|
|Gene amplication||5'-GGCGACTGCGAATGCTAT-3'||5'-GGCAGATCATCACCAACTCC-3' (used to amplify Bph14 )|
|5'-CTACAGGCAGCCAGCAGAT-3'||5'-TCCTGTCAGATTCTTGCACTG-3' (used to amplify LRR domain )|
Bph14 was expressed constitutively in leaf sheaths,leaf blades, and roots.See Figure 2. For examining Bph14 activity in more detail, using transgenic plants carrying the fusion construct of the Bph14 promoter region and the GUS reporter gene. The expression of GUS in transgenic plants was detected mainly in the vascular tissue of various organs, including leaf sheaths and leaf blades. In cross-sections of these organs, GUS activity was strongly detected in the parenchyma cells bordering, xylem vessels and sieve tubes. For examining Bph14 activity in more detail, using transgenic plants carrying the fusion construct of the Bph14 promoter region and the GUS reporter gene. The expression of GUS in transgenic plants was detected mainly in the vascular tissue of various organs, including leaf sheaths and leaf blades. In cross-sections of these organs, GUS activity was strongly detected in the parenchyma cells bordering, xylem vessels and sieve tubes.See Figure 3.The Bph14-GFP fusion protein is localized in the cy2oplasm. See Figure 4.
Bph14 shares 83% sequence identity with its allele (Os03g0848700) in Nipponbare. Phylogenetic analysis revealed that Bph14 is closely related to other rice homologs and is divergent from the majority of known plant disease resistance proteins in other species. See Figure 5.
Plant defense responses to insects include the activation of pathways dependent on SA and JA/ethylene signaling molecules. There was no significant difference between the transgenic and the wild-type plants in transcript levels of the JA synthesis-related genes LOX(lipoxygenase) and AOS2 (allene oxide synthase 2) in 24 h after BPH infestation. At all subsequent time points, however, transcript levels of these genes were substantially lower in the transgenics than in wildtype plants. In addition, the ethylene signaling pathway receptor gene EIN2(ethylene insensitive 2) accumulated faster and at higher levels in the wild type than in transgenics. These results suggested that BPH feeding induced the defenses in the susceptible plants associated with a JA/ethylene-dependent pathway. However, transcript levels of the SA synthesis-related genes EDS1(enhanced disease susceptibility 1), PAD4(phytoalexin deficient 4), PAL(phenylalanine ammonia-lyase), and ICS1 (isochorismate synthase 1)  were higher in the transgenic plants than in wild-type plants after BPH infestation, suggesting that Bph14may activate an SA-dependent resistance pathway after BPH feeding. NPR1(homolog of Arabidopsis nonexpressor of pathogenesis-related genes 1) is a key regulator of SAdependent systemic acquired resistance (SAR) that was found to enhance the expression of PR1b(basic pathogenesis-related gene 1). PR1bis suggested to be effective in inhibiting pathogen growth, multiplication, and/or spread and is responsible for the SAR in plants. The transcript level ofNPR1was also higher in the transgenic than in the wild-type plants. However, the higher transcript level of NPR1did not result in stronger induction of PR1b,suggestingthatthetranscriptlevelofPR1b was regulated by JA/ethylene signal in rice after BPH infestation. These results demonstrate thatBph14activates a NPR1-dependent, butPR1-independent, resistance after BPH feeding.
Labs working on this gene
- Key Laboratory of Ministry of Education for Plant Development Biology, College of Life Sciences, Wuhan University, Wuhan 430072, China
- National Center for Gene Research, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200233, China
- Shandong Rice Research Institute, Shandong Academy of Agricultural Sciences, Jinan 250100, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
- Bo Dua, Weilin Zhanga,Bingfang Liua, et al. (2009) Identification and characterization of Bph14, a gene conferring resistance to brown planthopper in rice.Proceedings of the National Academy of Sciences, 106(52): 22163-22168.
- Huang Z, He GC, Shu LH, et al. (2001) Identification and mapping of two brown planthopper resistance genes in rice. Theor Appl Genet 102:929–934.
- Jie Li, Qiuhong Chen, Liangquan Wang, et al. (2011) Biological effects of rice harbouring Bph14 and Bph15 on brown planthopper, Nilaparvata lugens. Pest Management Science, 67:528–534.
- Zhou Lei, Zhijun Chen, Xuyong Lang, et al. (2013) Development and validation of a PCR-based functional marker system for the brown planthopper resistance gene Bph14 in rice. Breeding Science, 63:347–352.
- Qiu D, et al. (2007) OsWRKY13 mediated rice disease resistance by regulating defenserelated genes in salicylate- and jasmonate-dependent signaling.Mol Plant Microbe Interact, 20:492–499.
- Chern M, Fitzgerald HA, Canlas PE, Navarre DA, Ronald PC (2005) Overexpression of a rice NPR1 homolog leads to constitutive activation of defense response and hypersensitivity to light. Mol Plant Microbe Interact18:511–520.