桃(Prunus persica)多数品种可以自花结实,花粉正常发育对产量至关重要,花粉发育异常影响自花授粉受精和坐果.因此,研究桃的花粉育性具有重要的产业和理论意义.本研究以不育品种'久硕'('JiuShuo',JS)与可育品种'久脆'('JiuCui',JC)及其杂交后代为实验材料对花粉育性基因进行研究.花药解剖观察结果表明,JS花粉不育发生在单核小孢子期,绒毡层细胞质不能正常浓缩、退化.RNA测序(RNA sequencing,RNA-seq)分析结果表明,与绒毡层细胞程序性死亡和花粉外壁形成相关的途径-糖代谢、苯丙氨酸代谢、脂肪酸的生物合成和氧化还原反应在四分体和单核小孢子时期被显著富集.qRT-PCR检测可育品种JC、不育品种JS以及JS×JC后代中相关基因表达模式发现,细胞色素P450703A2(cytochrome P450703A2,PpCYP703A2)(GenBank No.XM_007220109)、4-香豆酸-CoA连接酶-1(4-coumarate-CoA ligase-like 1,Pp4CL)(GenBank No.XM_007225695)和ABC转运蛋白G家族成员26(ABC transporter G family member 26,PpABCG26)(GenBank No.XM_020565361)参与了花粉育性的调控.本研究为桃的花粉育性研究挖掘到新的基因,也为进一步揭示桃花粉育性的分子机制提供了新的理论依据.

为了确定侵染深州蜜桃的病毒和类病毒种类,利用RT-PCR和qRT-PCR的方法对侵染桃树的7种病毒和类病毒进行了检测.RT-PCR病毒鉴定结果表明,深州蜜桃感染了苹果褪绿叶斑病毒(ACLSV)、李树皮坏死茎纹孔伴随病毒(PBNSPaV)、李属坏死环斑病毒(PNRSV)和啤酒花矮化类病毒(HSVd),在深州蜜桃果实中没有鉴定到李矮缩病毒(PDV)、樱桃绿环斑驳病毒(CGRMV)、杏假褪绿叶斑病毒(APCLSV).qRT-PCR检测结果进一步表明李属坏死环斑病毒(PNRSV)侵染了深州蜜桃,其病毒RNA表达量最低.利用RT-PCR开发出高效的多重检测体系,能够同时检测ACLSV,PBNSPaV和HSVd病毒.

[目的]探明外源ABA处理对桃抗寒性的影响.[方法]以不同质量浓度ABA(0、25、50、75、100 mg·L-1)喷施处理的21世纪和久硕1年生枝条为试验材料,分别进行人工模拟低温(0、-5、-10、-15、-20、-25、-30℃)处理,研究相对电导率和丙二醛(MDA)、可溶性蛋白、可溶性糖及内源激素(ABA、GA、IAA、CTK)含量以及ABA/GA的差异.[结果]在低温胁迫下,外源ABA处理的21世纪和久硕枝条可溶性蛋白、可溶性糖含量较对照均增加,丙二醛(MDA)含量和相对电导率均降低,ABA、GA、IAA、CTK含量及ABA/GA均呈无规律变化.用隶属函数法对低温胁迫下各项抗寒指标进行综合评价,不同ABA质量浓度对21世纪抗寒影响顺序为50＞75＞100＞25＞0 mg·L-1(CK),不同ABA质量浓度对久硕抗寒影响顺序为50＞25＞75＞100＞0 mg·L-1(对照).[结论]50 mg·L-1ABA为最佳质量浓度,能有效缓解冻害,提高抗寒性.

为确定苹果MdGolSs基因在低温和盐胁迫下的潜在功能,对苹果8个MdGolSs进行蛋白结构和进化树等生物信息学分析,并做低温和盐胁迫处理表达分析.结果表明,8个MdGolSs蛋白均具有保守的"PLN00176"结构域;进化树分析发现8个MdGolSs成员可分为3组,且MdGolS4和MdGolS6,MdGolS1和Md-GolS8,MdGolS3和MdGolS7,MdGolS2和MdGolS5进化关系较近;8个MdGolSs成员在低温和盐胁迫条件下均不同程度地受诱导表达,表明MdGolSs可能与苹果抗低温和盐胁迫响应有关.

The carotenoid composition and content in the yellow sarcocarp peach are a direct indicator of quality. Therefore, discoveries regarding the identification of candidate genes related to carotenoid accumulation and their regulatory mechanisms would be beneficial for yellow sarcocarp peach breeding. In this study, the white sarcocarp peach cultivar '21shiji' (21SJ) and its unique yellow sarcocarp bud mutation individual (21BM) were used for carotenoid determination and candidate gene discovery based on UPLC-APCI-MS/MS and RNA-seq. In total, 11 carotenoid compositions showed significant differences between '21SJ' and '21BM', including four carotenes and seven xanthophylls. Furthermore, the accumulation of β-carotene, zeaxanthin, β-cryptoxanthin, antheraxanthin, violaxanthin, and capsanthin showed different tendencies between '21SJ' and '21BM' during the ripening stage and influenced '21BM' yellow sarcocarp formation. Using transcriptome analysis, we found that the differential expression of candidate genes PpZEP, PpVDE1, PpCCD4, and PpCCS were major influencing factors. Two transfactors, PpbHLH14 and PpMYB73, were significantly related to PpZEP, PpVDE1, PpCCD4, and PpCCS expression and carotenoid accumulation after weighted gene co-expression network analysis. The identified structural genes and transcription factors in this study will further enrich carotenoid accumulation regulatory mechanism in peach and will provide an important theoretical reference for yellow sarcocarp peach breeding.

2021年1月河北各地发生了几十年一遇的低温,为了探明低温后各桃品种的冻害情况,采用实地调查、问卷调查等方式在各地进行调查.结果表明,调查的60个桃品种中,20个品种未发生冻害,40个品种受到不同程度的冻害,冻害面积1892.53 hm2,占当年桃栽培面积的2.18％.不同桃品种抗寒力不同,在不同地区的冻害表现不同,同时也受到地形、地势的影响.针对调查结果,对主要桃品种的适应范围提出了建议.

2020年冬季,深州地区遭遇了几十年不遇的极端低温,地面最低温度达到-23.2℃,桃园发生了不同程度的冻害.本调查旨在摸清深州市不同桃品种的冻害情况,为今后桃品种的区域化栽培提供参考.