Trash to treasure:lactate and protein lactylation in maize root impacts response to drought

Lactate,protein lactylation(Kla),and specifically histone lactylation have recently been shown to regulate antipathogenic immune responses in mammals.Herein,after we confirmed the presence and accumulation of lactate in maize roots under drought conditions,a lactylome profiling analysis revealed that Kla modifications were invariably present in maize roots,that there were obvious differences in the lactylomes of drought-sensitive(B73)vs.drought-tolerant(Jing2416)lines,and that growing Jing2416 under drought conditions caused significant decreases in the lactylation of multiple enzymes responsible for fatty acid degradation.Inspired by findings of histone-Kla based epigenetic regulation of immune functions in animals,we initially discovered 37 Kla sites on 16 histones in the maize genome,and again detected obvious differential histone Klamediated trends between two lines by Ch IP-Seq.Notably,only 2.7%of genes with differential histone Kla peaks detected during drought stress were commonly present in both lines,a finding demonstrating that abiotic stress triggers distinct epigenetic activities in diverse germplasm while also strongly supporting that a histone Kla layer of regulation is associated with physiological responses to drought stress.Interestingly,exogenous application of spermidine improved the drought tolerance of B73and substantially altered the levels of lactate,protein lactylation,and histone Kla modification.Thus,beyond extending the known domain of Kla-based biochemical and epigenetic regulation from animal immunity to plant stress physiology,our study suggests the physiological,biochemical,and genetic function of“the best-known metabolic waste”,lactate.

The HuangZaoSi Maize Genome Provides Insights into Genomic Variation and Improvement History of Maize

Maize is a globally important crop that was a classic model plant for genetic studies. Here, we report a 2.2 Gb draft genome sequence of an elite maize line, HuangZaoSi (HZS). Hybrids bred from HZS-improved lines (HILs) are planted in more than 60% of maize fields in China. Proteome clustering of six completed sequeneed maize genomes show that 638 proteins fall into 264 HZS-specific gene families with the majority of contributions from tandem duplication events. Resequencing and comparative analysis of 40 HZSrelated lines reveals the breeding history of HILs. More than 60% of identified selective sweeps were clustered in identity.by.descent conserved regions, and yield-related genes/QTLs were enriched in HZS characteristic selected regions. Furthermore, we dem on strated that HZS-specific family genes were not uniformly distributed in the genome but enriched in improvement/function.related genomic regions. This study provides an important and novel resource for maize genome research and expands our knowledge on the breadth of genomic variation and improvement history of maize.