The online version contains supplementary material available at 10.1007/s11032-021-01267-4.

The online version contains supplementary material available at 10.1007/s11032-021-01252-x.

The online version contains supplementary material available at 10.1007/s11032-021-01238-9.

The online version contains supplementary material available at 10.1007/s11032-021-01228-x.

The online version contains supplementary material available at 10.1007/s11032-021-01216-1.

The domestication and improvement of maize resulted in radical changes in shoot architecture relative to its wild progenitor teosinte. In particular, critical modifications involved a reduction of branching and an increase in inflorescence size to meet the needs for human consumption and modern agricultural practices. Maize is a major contributor to global agricultural production by providing large and inexpensive quantities of food, animal feed, and ethanol. Maize is also a classic system for studying the genetic regulation of inflorescence formation and its enlarged female inflorescences directly influence seed production and yield. Studies on the molecular and genetic networks regulating meristem proliferation and maintenance, including receptor-ligand interactions, transcription factor regulation, and hormonal control, provide important insights into maize inflorescence development and reveal potential avenues for the targeted modification of specific architectural traits. In this review, we summarize recent findings on the molecular mechanisms controlling inflorescence formation and discuss how this knowledge can be applied to improve maize productivity in the face of present and future environmental challenges.

Maize is a heterosis-utilizing crop species, and the application of maize hybrids has significantly improved total maize yields worldwide. Breeding pure lines is the most important part of heterosis utilization. The double haploid (DH) breeding technology is the approach rising recently in breeding pure lines; compared to the conventional recurrent-selfing method, it can significantly accelerate the crop breeding process. Similar to molecular breeding and transgenic techniques, maize DH breeding has been playing an increasingly important role in commercial breeding and is becoming the core technique in modern maize breeding. In this review, we summarize recent progress in maize DH breeding and put forth our opinions on the future development of double haploid techniques in modern maize breeding.

Elucidation of the genomic organizations of transgene insertion sites is essential for the genetic studies of transgenic plants. Herein, we establish an analysis pipeline that identifies the transgene insertion sites as well as the presence of vector backbones, through de novo genome assembly with high-throughput sequencing data in two transgenic soybean lines, AtYUCCA6-#5 and 35S-UGT72E3/2-#7. Sequencing data of approximately 28× and 29× genome coverages for each line generated by high-throughput sequencing were de novo assembled. The databases generated from the de novo assembled sequences were used to search contigs that contained putative insertion sites and their flanking sequences (integration sites) of transgene fragments using transgenic vector sequences as queries. The predicted integration site sequences, which are located at three annotated genes that might regulate plant development or confer disease resistance, were then confirmed by local alignment against the soybean reference genome and PCR amplification. As results, we revealed the precise transgene-flanking sequences and sequence rearrangements at insertion sites in both the transgenic lines, as well as the aberrant insertion of a transgene fragment. Consequently, relative to experimental or enrichment technologies, our approach is straightforward and time-effective, providing an alternative method for the identification of insertion sites in transgenic plants.

Maize (Zea mays L.) is an important crop around the world, but its growth and production can be severely limited by waterlogging. In response to waterlogging stress, elaborate regulatory mechanisms have evolved in maize under both natural and artificial selection. Some research efforts involving genetic, genomic, and molecular strategies have focused on waterlogging stress biology in maize. Waterlogging affects the morphology, anatomy, physiology, and biochemistry of maize. The ability to improve waterlogging tolerance in maize breeding programs hinges on a detailed understanding of the genetic basis for waterlogging tolerance in some maize lines. In this review, we summarize the current understanding of this genetic basis.

Male reproductive development is vital for crop seed production. However, the mechanism underlying remains largely unknown. Here, we isolated a male sterile mutant osgelp34-1 in rice. Cytological analysis indicated that the mutant exhibited delayed degradation of anther wall layers and abnormal pollen development, which resulted in the production of shrunk and non-viable pollen grains. MutMap and CRISPR/Cas9 analysis confirmed that a point mutation in OsGELP34 is responsible for the male sterile phenotype. OsGELP34 is highly expressed in reproductive tissues and encodes a putative GDSL lipase. OsGELP34 protein is located to the endoplasmic reticulum (ER) and conserved in land plants. Collectively, our findings elaborated that OsGELP34 plays a vital role in rice male reproduction and has potential applications in rice hybrid breeding.