Germ cells are indispensable carriers of genetic information from one generation to the next. In contrast to the well-understood process in animals, information on the mechanism of germ cell initiation in plants is very limited. / was previously identified as an essential regulator of diploid germ cell (archesporial cell) differentiation in the stamens and ovules of Arabidopsis (). Although () transcription is activated by the floral organ identity regulator AGAMOUS and epigenetically regulated by SET DOMAIN GROUP2, little is known about the regulation of the SPL protein. Here, we report that the protein kinases MPK3 and MPK6 can both interact with SPL in vitro and in vivo and can phosphorylate the SPL protein in vitro. In addition, phosphorylation of the SPL protein by MPK3/6 is required for SPL function in the Arabidopsis anther, as measured by its effect on archesporial cell differentiation. We further demonstrate that phosphorylation enhances SPL protein stability. This work not only uncovers the importance of SPL phosphorylation for its regulatory role in Arabidopsis anther development, but also supports the hypothesis that the regulation of precise spatiotemporal patterning of germ cell initiation and that differentiation is achieved progressively through multiple levels of regulation, including transcriptional and posttranslational modification.

The ubiquitin C-terminal hydrolase (UCH) and ubiquitin-specific processing protease (UBP) protein families both function in protein deubiquitination, playing important roles in a wide range of biological processes in animals, fungi, and plants. Little is known about the functions of these proteins in rice (Oryza sativa), and the numbers of genes reported for these families have not been consistent between different rice database resources. To further explore their functions, it is necessary to first clarify the basic molecular and biochemical nature of these two gene families. Using a database similarity search, we clarified the numbers of genes in these two families in the rice genome, examined the enzyme activities of their corresponding proteins, and characterized the expression patterns of all OsUCH and representative OsUBP genes. Five OsUCH and 44 OsUBP genes were identified in the rice genome, with four OsUCH proteins and 10 of 16 tested representative OsUBP proteins showing enzymatic activities. Two OsUCHs and five OsUBPs were found to be preferentially expressed in the early development of rice stamens. This work thus lays down a reliable bioinformatic foundation for future investigations of genes in these two families, particularly for exploring their potential roles in rice stamen development.

Germ cells (GCs) are the key carriers delivering genetic information from one generation to the next. In a majority of animals, GCs segregate from somatic cells during embryogenesis by forming germlines. In land plants, GCs segregate from somatic cells during postembryonic development. In a majority of angiosperms, male GCs (archesporial cells) initiate at the four corners of the anther primordia. Little is known about the mechanism underlying this initiation. Here, we discovered that the dynamic auxin distribution in developing anthers coincided with GC initiation. A centripetal auxin gradient gradually formed toward the four corners where GCs will initiate. Local auxin biosynthesis was necessary for this patterning and for GC specification. The GC determinant protein SPOROCYTELESS/NOZZLE (SPL/NZZ) mediated the effect of auxin on GC specification and modified auxin biosynthesis to maintain a centripetal auxin distribution. Our work reveals that auxin is a key factor guiding GC specification in Arabidopsis anthers. Moreover, we demonstrate that the GC segregation from somatic cells is not a simple switch on/off event but rather a complicated process that involves a dynamic feedback circuit among local auxin biosynthesis, transcription of SPL/NZZ, and a progressive GC specification. This finding sheds light on the mystery of how zygote-derived somatic cells diverge into GCs in plants.

Germ cells (GCs) transmit genetic information from one generation to the next. Unlike animal GCs, plant GCs are induced post-embryonically, forming locally from somatic cells. This induction is coordinated with organogenesis and might be guided by positional cues. In angiosperms, male GCs initiate from the internal layers at the four corners of the anther primordia and are gradually enclosed by parietal cell (PC) layers, leading to a concentric GC-PC pattern. However, the underlying mechanism of GC initiation and GC-PC pattern formation is unclear. Auxin affects pattern formation3 and anther development. However, whether GC formation involves auxin remains unknown. We report that the auxin distribution in pre-meiotic anthers parallels GC initiation, forming a centripetal gradient between the outer primordial cells and the inner GCs. The auxin biosynthesis genes TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS 1 (TAA1) and TRYPTOPHAN AMINOTRANSFERASE RELATED 2 (TAR2) are responsible for this patterning and essential for GC specification. SPOROCYTELESS/NOZZLE (SPL/NZZ, a determinant for GC specification) mediates the effect of auxin on GC specification, modulates auxin homeostasis, and maintains centripetal auxin patterning. Our results reveal that auxin is a key factor guiding GC specification in Arabidopsis anthers.

Aiming at the disadvantage of power plant sootblowing system presently, this paper takes 330MW unit boiler as research object, firstly calculates boiler optimal sootblowing frequency and cleaning coefficient when the heat net income of heat absorbing surface is maximum. And then based on neural network software, both boiler convection heat absorbing surface and radiate heat absorbing surface are implemented real-time monitoring by using DCS data. At the same time, it compares monitoring cleaning coefficient with critical cleaning coefficient real-time, and the optimized system will alarm and instructs the operator to take sootblowing command when it requirements. The reality application performence in power plant has proved that this system have great advantage and practicability in energy-saving.