Identification and Preliminary Functional Analysis of the BpLUXs Gene in Betula platyphylla Suk.

doi:10.7525/j.issn.1673-5102.2026.03.003

Abstract

Abstract:

Photoperiod serves as the key environmental cue governing seasonal growth and growth cessation in forest trees. Within the perception and transduction of photoperiodic signals， LUX ARRHYTHMO（LUX）， a core component of the circadian clock Evening Complex（EC）， plays a pivotal role. In the present study， a total of 47 BpLUX homologous genes were identified through genome-wide analysis in the reference genome of Betula platyphylla. Bioinformatic analyses revealed that BpLUX1， BpLUX5， and BpLUX18 harbor typical Evening Element（EE） cis-acting elements. All three genes possessed characteristic MYB conserved domains， while BpLUX1 and BpLUX5 additionally exhibited typical circadian rhythmic expression patterns. Using CRISPR/Cas9-mediated genome editing， loss-of-function mutants for BpLUX1（bplux1） were successfully generated， whereas targeted knockout of BpLUX5 proved unsuccessful. Phenotypic characterization demonstrated that under short-day（SD） conditions， wild-type birch ceased growth almost entirely by day 19 in response to shortened photoperiods， whereas bplux1 mutants remained actively growing. Furthermore， while no significant difference in plant height was observed in wild-type plants， bplux1 mutants displayed significantly increased height， exhibiting a delayed growth cessation phenotype. These findings indicate that BpLUX1 is a key gene mediating short-day responses and growth cessation in birch. Transcriptome analysis further revealed that under SD conditions， eleven differentially expressed genes（DEGs） were down-regulated in bplux1 mutants， including BpRCAR1 （Regulatory Component of ABA Receptor 1） involved in ABA （abscisic acid） signaling， whereas seven DEGs were up-regulated， including BpRGL1（RGA-Like1） associated with GA （gibberellin） signaling. Notably， potential binding sites between BpLUX1 and key DEGs in ABA and GA signaling pathways were identified， suggesting that BpLUX1 may influence growth cessation through modulation of phytohormone signaling. Collectively， this study provides a theoretical basis for understanding the role of BpLUX1 in photoperiod-regulated growth cessation in birch.

Key words: Betula platyphylla, BpLUX, photoperiod, growth cessation

CLC Number:

S714.7

Mengting PAN, Yueying LIU, Zhimin ZHENG. Identification and Preliminary Functional Analysis of the BpLUXs Gene in Betula platyphylla Suk.[J]. Bulletin of Botanical Research, 2026, 46(3): 411-424.

Figures/Tables 8

Table 1

Table 2

Table 3

BpLUXs genes alignment results

基因名称 Gene name	基因号 Gene ID	比对率 Identity/%	比对长度 Alignment length/bp	氨基酸数目 Number of amino acids/aa	等电位点 Theoretical pI	相对分子质量 Relative molecular mass/Da	亚细胞定位 Subcellular location
BpLUX1	Bplat_h1_10G00567	54.472	246	301	5.47	32 910.07	细胞核Nucleus
BpLUX2	Bplat_h1_14G01337	61.789	123	321	6.19	34 563.60	细胞核Nucleus
BpLUX3	Bplat_h1_08G02011	43.966	116	670	6.08	71 886.79	细胞核Nucleus
BpLUX4	Bplat_h1_08G01216	56.962	79	680	5.94	74 370.65	细胞核Nucleus
BpLUX5	Bplat_h1_01G00318	63.235	68	694	5.97	76 202.68	细胞核Nucleus
BpLUX6	Bplat_h1_12G02326	62.319	69	714	5.38	78 100.19	细胞核Nucleus
BpLUX7	Bplat_h1_11G01513	32.911	158	737	5.18	81 496.51	细胞核Nucleus
BpLUX8	Bplat_h1_06G00273	58.730	63	483	5.10	48 822.07	细胞核Nucleus
BpLUX9	Bplat_h1_08G01998	46.067	89	188	5.51	20 938.59	细胞核Nucleus
BpLUX10	Bplat_h1_06G00274	58.730	63	1051	5.81	118 236.64	细胞核Nucleus
BpLUX11	Bplat_h1_01G01163	37.671	146	605	5.67	67 851.41	细胞核Nucleus
BpLUX12	Bplat_h1_05G00214	48.837	86	456	7.98	52 252.68	细胞核Nucleus
BpLUX13	Bplat_h1_11G02231	40.426	94	427	6.44	46 880.03	细胞核Nucleus
BpLUX14	Bplat_h1_02G00164	53.333	60	560	6.08	62 528.25	细胞核Nucleus
BpLUX15	Bplat_h1_06G01349	56.897	58	501	6.00	54 793.90	细胞核Nucleus
BpLUX16	Bplat_h1_14G02337	53.623	69	419	7.29	46 884.77	细胞核Nucleus
BpLUX17	Bplat_h1_04G00221	54.286	70	355	8.25	39 420.90	细胞核Nucleus
BpLUX18	Bplat_h1_07G02471	60.000	55	322	7.71	35 163.07	细胞核Nucleus
BpLUX19	Bplat_h1_08G03288	54.545	55	351	6.81	38 983.83	细胞核Nucleus
BpLUX20	Bplat_h1_03G01346	43.023	86	463	7.12	50 724.45	细胞核Nucleus
BpLUX21	Bplat_h1_08G00772	37.963	108	468	5.35	53 375.19	细胞核Nucleus
BpLUX22	Bplat_h1_14G00212	37.209	129	349	7.73	38 959.20	细胞核Nucleus
BpLUX23	Bplat_h1_06G00533	45.455	66	323	5.72	35 639.67	细胞核Nucleus
BpLUX24	Bplat_h1_09G01482	51.786	56	395	6.59	44 367.63	细胞核Nucleus
BpLUX25	Bplat_h1_12G00064	44.118	68	389	6.48	42 308.72	细胞核Nucleus
BpLUX26	Bplat_h1_03G00243	55.556	54	484	5.51	53 293.29	细胞核Nucleus
BpLUX27	Bplat_h1_02G00362	50.746	67	280	6.98	31 521.49	细胞核Nucleus
BpLUX28	Bplat_h1_08G01864	54.545	55	309	8.07	34 789.69	细胞核Nucleus
BpLUX29	Bplat_h1_06G02707	38.281	128	350	6.90	39 394.52	细胞核Nucleus
BpLUX30	Bplat_h1_07G01375	43.478	92	430	6.04	48 967.34	细胞核Nucleus
BpLUX31	Bplat_h1_07G02472	58.491	53	335	6.57	36 684.08	细胞核Nucleus
BpLUX32	Bplat_h1_07G02207	36.634	101	302	9.31	34 359.32	细胞核Nucleus
BpLUX33	Bplat_h1_05G01228	48.718	78	460	5.59	50 655.07	细胞核Nucleus
BpLUX34	Bplat_h1_10G00179	54.717	53	366	8.70	41 561.47	细胞核Nucleus
BpLUX35	Bplat_h1_14G01211	52.727	55	295	6.34	31 664.44	细胞核Nucleus
BpLUX36	Bplat_h1_12G00245	38.542	96	296	8.75	33 023.06	细胞核Nucleus
BpLUX37	Bplat_h1_14G01650	49.091	55	425	7.09	47 626.14	细胞核Nucleus
BpLUX38	Bplat_h1_12G01893	35.484	93	193	10.18	21 718.78	细胞核Nucleus
BpLUX39	Bplat_h1_12G01896	46.667	60	345	8.63	38 971.68	细胞核Nucleus
BpLUX40	Bplat_h1_02G00314	45.000	60	370	9.30	41 774.52	细胞核Nucleus
BpLUX41	Bplat_h1_11G00872	45.000	60	419	7.86	46 573.83	细胞核Nucleus
BpLUX42	Bplat_h1_11G01688	54.717	53	229	7.87	26 381.96	细胞核Nucleus
BpLUX43	Bplat_h1_14G01651	51.852	54	319	8.96	37 063.91	细胞核Nucleus
BpLUX44	Bplat_h1_14G01652	44.595	74	288	7.17	33 126.49	细胞核Nucleus
BpLUX45	Bplat_h1_14G00254	50.943	53	258	7.71	29 272.00	细胞核Nucleus
BpLUX46	Bplat_h1_13G02359	40.244	82	342	9.18	38 879.09	细胞核Nucleus
BpLUX47	Bplat_h1_07G02426	60.606	33	149	9.15	15 969.02	细胞核Nucleus

Table 3

Fig.1

Fig.2

Fig.3

Fig.4

Fig.5

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引物名称 Primer name	引物序列（5′→3′） Primer sequences（5′→3′）
BpTUB-F	TCAACCGCCTTGTCTCTCAGG
BpTUB-R	TGGCTCGAATGCACTGTTGG
BpLUX1-RT-F	GTTCTCTGCCAGCGATAGCTTG
BpLUX1-RT-R	CGCGCAGTCGATTCTTCTAGACTT
BpLUX5-RT-F	TTGTCTTGGAGAACCTGCTTCGT
BpLUX5-RT-R	TGACAGGTAGGTCCATCTCAAGG
BpLUX18-RT-F	CATCATGCGGACAATGAATGTGAAG
BpLUX18-RT-R	TTGCACTTCCATCTGTGCTCTC

引物名称 Primer name	引物序列（5′→3′） Primer sequences（5′→3′）
BpLUX1-T1-F	TTCGTCGGCGTTCAGCATCTCT
BpLUX1-T1-R	AACCAGAGATGCTGAACGCCGA
BpLUX1-T2-F	TTCGTGGACGTTGTGGGCCACCT
BpLUX1-T2-R	AACAGGTGGCCCACAACGTCCAC
BpLUX5-T1-F	TTCGAGCTTGTGGGCCTTGAGA
BpLUX5-T1-R	AACTCTCAAGGCCCACAAGCTC
BpLUX5-T2-F	TTCGCAAGTTTGTTGCTGCTGTTC
BpLUX5-T2-R	AACGAACAGCAGCAACAAACTTGC
PSC1-F	TTGGCCGATTCATTAATGCAGC
Test-BpLUX1-T1-F	ATGATGGGTGAGGACGTGAAGATG
Test-BpLUX1-T1-R	CAAGCTATCGCTGGCAGAGAAC
Test-BpLUX1-T2-F	AAGTCTAGAAGAATCGACTGCGCG
Test-BpLUX1-T2-R	GACGACGCAAACAACTGGTGGTC