USDA-ARS Crop Production and Pest Control Research Unit, West Lafayette, IN 47907, USA.
Plant Physiol Biochem. 2010 Jan;48(1):54-61. doi: 10.1016/j.plaphy.2009.10.004. Epub 2009 Oct 27.
A sequence encoding a putative type-1 lipid transfer protein from wheat (Triticum aestivum L. em Thell) was identified through 'GeneCalling', an mRNA profiling technology. The mRNA for the Hfr-LTP (Hessian fly-responsive lipid transfer protein) gene decreased in abundance (196-fold) in susceptible wheat plants over the first eight days of attack by virulent Hessian fly larvae (Mayetiola destructor Say). Hfr-LTP encodes a putative protein containing eight cysteine residues that are conserved among plant LTPs and are responsible for correct protein folding through formation of disulfide bridges. Twelve hydrophobic amino acids in addition to arginine, glycine, proline, serine, threonine and tyrosine, plus an LTP signature sequence were present in conserved positions. A highly conserved signal peptide sequence was also present. Although attack by one virulent larva was sufficient to cause a decrease in Hfr-LTP mRNA abundance, higher infestation levels led to near silencing of the gene. Hfr-LTP transcript levels were not affected by other biotic factors (feeding by bird cherry-oat aphid, Rhopalosiphum padi L., and fall armyworm larvae, Spodoptera frugiperda Smith) or abiotic factors tested (mechanical wounding or treatment with abscisic acid, methyl jasmonate, or salicylic acid). Comparison to a previously described Hessian fly-responsive wheat LTP gene, TaLTP3, confirmed an initial increase in TaLTP3 mRNA in resistant plants. However, when quantified through eight days after egg hatch, responsiveness to infestation level and a marked decrease in susceptible plant TaLTP3 mRNA abundance were detected, as was seen for Hfr-LTP. Possible functions of LTP gene products in wheat-Hessian fly interactions are discussed.
通过 mRNA 谱分析技术“基因调用”，从小麦（Triticum aestivum L. em Thell）中鉴定出一个编码假定的 1 型脂转移蛋白的序列。在感染致命的玉米穗蝇幼虫（Mayetiola destructor Say）后的头 8 天内，易感小麦植株中 Hfr-LTP（黑森蝇反应性脂转移蛋白）基因的 mRNA 丰度（196 倍）下降。Hfr-LTP 编码一种假定的蛋白，该蛋白含有 8 个半胱氨酸残基，这些残基在植物 LTP 中保守，通过形成二硫键来正确折叠蛋白。除精氨酸、甘氨酸、脯氨酸、丝氨酸、苏氨酸和酪氨酸外，还有 12 个疏水性氨基酸以及 LTP 特征序列存在于保守位置。还存在一个高度保守的信号肽序列。尽管一个有活力的幼虫的攻击足以导致 Hfr-LTP mRNA 丰度降低，但更高的侵染水平导致该基因几乎沉默。Hfr-LTP 转录本水平不受其他生物因素（鸟桃蚜、禾谷缢管蚜和秋粘虫幼虫的取食）或测试的非生物因素（机械损伤或用脱落酸、茉莉酸甲酯或水杨酸处理）的影响。与之前描述的黑森蝇反应性小麦 LTP 基因 TaLTP3 相比，证实了抗性植物中 TaLTP3 mRNA 的初始增加。然而，当从卵孵化后 8 天进行定量时，发现对侵染水平的反应性以及易感植物 TaLTP3 mRNA 丰度的显著降低，与 Hfr-LTP 一样。讨论了 LTP 基因产物在小麦-玉米穗蝇相互作用中的可能功能。
