Salt tolerance of transgenic poplar by the introduction of AtNHX1 gene

doi:10.3773/j.issn.1005-264x.2010.05.010

Abstract

Abstract:

Aim Our objective was to test whether the overexpression of the Arabidopsis thaliana tonoplast Na⁺/H⁺ antiporter gene, AtNHX1, can improve salt tolerance in poplar.

Methods Transgenic and wild-type poplar (Populus × euramericana ‘Neva’) were subjected to low salt and high salt treatments. We investigated the effects of NaCl on the transgenic and wild-type poplar by measuring growth parameters, chlorophyll (Chl) and carotenoid (Car) content, net photosynthetic rate (P_n), maximal photochemical efficiency of PSII (F_v/F_m), ion content, leaf malondialdehyde (MDA) and electrolytic leakage after 30 days.

Important findings Compared with the control, the growth of wild-type plants was restrained significantly in the presence of both low salt and high salt. The dry weight of wild-type plants was significantly lower under salt stress than that of control, the dry weight decreased gradually with increasing NaCl concentration and their dry weight under high salt was just 50% of the control. However, the dry weight of transgenic plants in low salt was similar to the control up to the high salt treatment, where their dry weight was 74% of the control. Moreover, the dry weight of transgenic plants was significant higher than that of wild-type in both NaCl treatments, and the discrepancy of dry weight was increased with increasing NaCl concentration. In the presence of NaCl, Chl and Car content of transgenic plants were significantly higher than that of wild-type, and the transgenic plants maintained a remarkably high P_n and F_v/F_m. Although these transgenic plants accumulated more Na⁺ in their roots and leaf tissues under salinity conditions compared with the wild-type plants, they absorbed more K⁺and maintained a higher K⁺/Na⁺ratio. Moreover, these transgenic plants kept a lower MDA and electrolytic leakage level than that of wild-type. These findings indicate that transformation of AtNHX1 gene into poplar can confer plants more tolerance to salinity than wild-type poplar by maintaining better growth, higher Chl and Car content and improved P_n and F_v/F_m. These transgenic plants have potential for further applications in saline soil.

Key words: AtNHX1, ion compartmentation, Populus × euramericana ‘Neva’, salt tolerance, transgenic plant

JIANG Chao-Qiang, ZHENG Qing-Song, LIU Zhao-Pu, XU Wen-Jun, LI Hong-Yan, LI Qing. Salt tolerance of transgenic poplar by the introduction of AtNHX1 gene[J]. Chin J Plant Ecol, 2010, 34(5): 563-570.

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URL: https://www.plant-ecology.com/EN/10.3773/j.issn.1005-264x.2010.05.010

https://www.plant-ecology.com/EN/Y2010/V34/I5/563

Figures/Tables 7

References 25

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品系 Strain	对照 Control	低盐处理 Low salt treatment	高盐处理 High salt treatment
Tr	0.019 ± 0.004	0.395 ± 0.036	0.715 ± 0.035
Wt	0.019 ± 0.004	0.412 ± 0.023	0.745 ± 0.015

品系 Strain	对照 Control	低盐处理 Low salt treatment	高盐处理 High salt treatment
Tr	0.019 ± 0.004	0.395 ± 0.036	0.715 ± 0.035
Wt	0.019 ± 0.004	0.412 ± 0.023	0.745 ± 0.015

处理 Treatment	基因型 Gene type	干重 Dry weight (g DW·plant^-1)	p < 0.05	p < 0.01
对照 Control	Tr	71.57 ± 2.74^a	a	A
对照 Control	Wt	70.08 ± 4.36^a	a	A
低盐 Low salt	Tr	65.44 ± 4.82^a	a	A
低盐 Low salt	Wt	51.58 ± 2.82^b	b	B
高盐 High salt	Tr	53.16 ± 2.38^b	b	B
高盐 High salt	Wt	35.15 ± 1.99^c	c	C

处理 Treatment	基因型 Gene type	干重 Dry weight (g DW·plant^-1)	p < 0.05	p < 0.01
对照 Control	Tr	71.57 ± 2.74^a	a	A
对照 Control	Wt	70.08 ± 4.36^a	a	A
低盐 Low salt	Tr	65.44 ± 4.82^a	a	A
低盐 Low salt	Wt	51.58 ± 2.82^b	b	B
高盐 High salt	Tr	53.16 ± 2.38^b	b	B
高盐 High salt	Wt	35.15 ± 1.99^c	c	C

处理 Treatment	基因型 Gene type	K⁺含量 K⁺ content (mmol·g^-1 DW)		Na⁺含量 Na⁺ content (mmol·g^-1DW)		K/Na比率 K/Na ratio
处理 Treatment	基因型 Gene type	根 Root	叶 Leaf	根 Root	叶 Leaf	根 Root	叶 Leaf
对照 Control	Tr	0.59 ± 0.05^a	0.81 ± 0.06^a	0.04 ± 0.00^e	0.04 ± 0.00^e	15.79 ± 2.06^a	21.11 ± 2.11^a
对照 Control	Wt	0.54 ± 0.06^ab	0.73 ± 0.07^ab	0.04 ± 0.00^e	0.04 ± 0.00^e	14.15 ± 1.57^b	19.88 ± 1.57^a
低盐 Low salt	Tr	0.55 ± 0.03^ab	0.77 ± 0.05^ab	0.38 ± 0.03^c	0.47 ± 0.01^c	1.44 ± 0.11^c	1.63 ± 0.08^b
低盐 Low salt	Wt	0.45 ± 0.04^cd	0.53 ± 0.05^c	0.33 ± 0.02^d	0.37 ± 0.01^d	1.35 ± 0.08^c	1.42 ± 0.15^b
高盐 High salt	Tr	0.51 ± 0.06^bc	0.70 ± 0.05^b	0.56 ± 0.03^a	0.79 ± 0.02^a	0.90 ± 0.09^c	0.88 ± 0.05^b
高盐 High salt	Wt	0.39 ± 0.04^d	0.40 ± 0.06^d	0.48 ± 0.03^b	0.57 ± 0.02^b	0.80 ± 0.12^c	0.71 ± 0.11^b