摘要:Plant breeding is both the science and art of developing elite crop cultivars by creating and reassembling desirable inherited traits for human benefit. From the bulk selection of wild plants for cultivation during early civilization to Mendelian genetics and genomics-assisted breeding in modern society, breeding methodologies have evolved over the last thousand years. In the past few decades, the “Green Revolution” through breeding of semi-dwarf wheat and rice varieties, and the use of heterosis and transgenic crops have dramatically enhanced crop productivity and helped prevent widespread famine (Hickey et al., 2019). Integration of these technologies can significantly improve breeding efficiency in the development of super crop varieties (Li et al., 2018). For example, a hybrid cotton variety CCRI63 and six related hybrid varieties account for nearly 90% of cotton production in the Yangtze River Basin (Wan et al., 2017; Wang et al., 2018). These varieties have successfully combined high yield, good quality, and biotic stress tolerance through the integration of conventional breeding, hybrid and genetically modified organism (GMO) technologies (Lu et al., 2019; Ma et al., 2019; Song et al., 2019). Unfortunately, such technology integration is not practical for most staple food crops, including rice and wheat, because of social or technical restrictions. Furthermore, plant breeding is still labor-intensive and time-consuming, and conventional breeding remains the leading approach for the release of commercial crop varieties worldwide. This is especially true for breeding cultivars and hybrids with high yield, good quality, and resistance to biotic or abiotic stresses (Liu et al., 2015; Gu et al., 2016). New germplasm, knowledge, and breeding techniques are required to breed the next generation of crop varieties.
摘要:目的阐明白藜芦醇(RSV)在猪精液冷冻保存中的应用效果及作用机制.创新点在冷冻过程中添加RSV,观察其对猪冻后精子抗冻能力的影响,并阐明其细胞凋亡作用机理.方法在猪精液的冷冻和解冻过程中添加1 mmol/L RSV,解冻后检测精子活力、线粒体膜电位、腺苷三磷酸(ATP)含量、凋亡水平和凋亡通路中相关基因的表达情况.结论(1)与鲜精相比,冷冻精液的活力、顶体完整性和质膜完整性均显著降低,冷冻前后RSV处理未能显著提高精子活力(0.44 vs. 0.40,P>0.05),但能显著提高顶体完整性(57.65% vs. 47.00%,P<0.05)和质膜完整性(46.67% vs. 38.85%,P<0.05).(2)解冻后精子线粒体膜电位显著下降,RSV的添加能提高精子膜电位水平. (3)冷冻解冻过程中添加RSV能显著降低精子的活性氧(ROS)水平(58.65% vs. 88.41%,P<0.05),增加精子的ATP含量(0.49 µmol/L vs. 0.25 µmol/L,P<0.05).(4)TUNEL凋亡检测后,冷冻精子的凋亡率(80.41%)与鲜精组(9.70%)相比显著增加(P<0.05),RSV处理能显著降低冻精的凋亡比例(68.32%,P<0.05).(5)实时荧光定量聚合酶链反应(qRT-PCR)的结果显示,猪精液冷冻后,无论是死亡受体介导凋亡途径中的相关基因(肿瘤坏死因子α(TNF-α)、TNF受体超族配体(FasL)和半胱氨酸的天冬氨酸蛋白水解酶8(Caspase-8)),还是线粒体介导凋亡途径中的相关基因(锰超氧化物歧化酶(MnSOD)、B淋巴细胞瘤-2(Bcl-2)、Bcl-2相关X蛋白质(Bax)和半胱氨酸的天冬氨酸蛋白水解酶9(Caspase-9)),均产生明显变化,RSV添加亦能显著改变其表达水平.综上所述,猪精液冷冻解冻过程中RSV添加虽未能显著提高精子活力,但仍表现为抗氧化保护效果,体现在改善了线粒体功能,并通过改变死亡受体和线粒体介导的凋亡途径中相关基因的表达水平,降低了冻后精子的细胞凋亡.