Cong L L, Zhang X Q, Yang F Y, Liu S J, Zhang Y W
Institute of Grassland Science, China Agricultural University, Beijing, China.
Department of Grassland Science, Sichuan Agricultural University, Ya'an, China.
Genet Mol Res. 2014 Oct 31;13(4):9122-33. doi: 10.4238/2014.October.31.28.
Reed canary grass (RCG) is a perennial grass traditionally cultivated for forage. It is also used as fuel to produce energy in Finland and Sweden, and other countries have expressed interest in the cultivation of RCG. In China, arable land is limited. Salinity is considered to be a major factor limiting plant crop development and productivity. To boost biofuel production of RCG and extend its range in saline soil, we seek to improve its salt tolerance. Proline acts as an osmolyte that accumulates when plants are subjected to abiotic stress. P5CS plays a crucial role in proline biosynthesis. We isolated a P5CS gene from RCG, designated B231P5CS (GenBank accession No. JQ622685). B231P5CS is a fragment (971 bp) that encodes a 323-amino acid polypeptide. We also cloned an actin gene fragment from RCG as a reference gene in expression analysis of B231P5CS gene. Expression analysis revealed that B231P5CS transcripts were upregulated in leaves after treatment with salt (200 mM NaCl) and that transcript levels of B231P5CS reached a maximum 12 h after exposure, which was 14.69 times the level in control plants. The trends of expression were exactly opposite in roots; transcripts were downregulated after salt treatment. Proline concentration increased in leaves after stress. In contrast, proline content of roots decreased up to 3.6-fold relative to controls. Changes in proline concentration after stress were correlated with B231P5CS expression. Our results suggest that B231P5CS is a stress-inducible gene and plays a non-redundant role in plant development. This gene may be used to improve stress tolerance of RGC and other bioenergy feedstock.
披碱草是一种多年生草本植物，传统上用于饲料种植。在芬兰和瑞典，它还被用作生产能源的燃料，其他国家也对披碱草的种植表现出兴趣。在中国，耕地有限。盐分被认为是限制农作物生长发育和生产力的主要因素。为了提高披碱草的生物燃料产量并扩大其在盐碱土壤中的种植范围，我们试图提高其耐盐性。脯氨酸作为一种渗透调节物质，在植物遭受非生物胁迫时会积累。P5CS在脯氨酸生物合成中起关键作用。我们从披碱草中分离出一个P5CS基因，命名为B231P5CS（GenBank登录号：JQ622685）。B231P5CS是一个971 bp的片段，编码一个323个氨基酸的多肽。我们还从披碱草中克隆了一个肌动蛋白基因片段，作为B231P5CS基因表达分析的参照基因。表达分析表明，用盐（200 mM NaCl）处理后，叶片中B231P5CS转录本上调，处理12 h后B231P5CS转录水平达到最高，是对照植株水平的14.69倍。根部的表达趋势正好相反；盐处理后转录本下调。胁迫后叶片中脯氨酸浓度增加。相比之下，根部脯氨酸含量相对于对照降低了3.6倍。胁迫后脯氨酸浓度的变化与B231P5CS的表达相关。我们的结果表明，B231P5CS是一个胁迫诱导基因，在植物发育中发挥非冗余作用。该基因可用于提高披碱草和其他生物能源原料的胁迫耐受性。
